The Most Inspiring Innovators And Entrepreneurs Under 40

Role: Founder of Nasty Gal

Age: 29

The hip, tattooed 29-year-old started Nasty Gal as an eBay store specializing in cool vintage women's clothing in 2006. Since then, the website has grown tremendously with more than $100 million in sales and more than 550,000 customers around the world. Last year the company was named the fastest-growing retailer by Inc. magazine, which also named Amoruso to their 30 Under 30 list this year.

Probably the most amazing thing of it all is that Sophia Amoruso had never worked in fashion before Nasty Gal — she was just a well-dressed young woman (and a college dropout) with a good eye for fashion.

Role: Pastry chef, owner of Dominique Ansel Bakery

Age: 35

Dominique Ansel's cronut — a doughnut-croissant hybrid rolled in sugar, filled with cream, and topped with glaze — took the food world by storm this summer like no other food trend has before. Customers line up between 5 and 6 a.m. (hours before the bakery opens) to snag one, shelling out $5 a pop.

Classically trained in Paris, Ansel took two months and tried more than 10 recipes to perfect the sweet pastry. Since the cronut craze, Ansel has also introduced a number of other daring new foods into the market including the frozen s'more and the magic soufflé — a chocolate Grand Marnier soufflé wrapped in an orange blossom brioche that, unlike other soufflés, never collapses.

Major brands have also realized Ansel's potential and are partnering with him to get their own around-the-block lines, like Shake Shack's recent partnership with him to create the limited-time-only Cronut Concrete.

Ansel's next creation will be his upcoming cookbook, "Dominique Ansel: The Secret Recipes," which comes out this month.

Role: Revolutionary street artist

Age: 38-39

Though no one knows the true identity of this stealthy graffiti artist, we do know that during an exclusive interview with The Guardian back in 2003, he was "white, 28, scruffy casual ... He looks like a cross between Jimmy Nail and Mike Skinner of the Streets."

And we also know that people all over the world swarm to get a look at his art before it's buried under new layers of paint. His art is eye-opening and proudly political, screaming all the things many people think but are afraid to say themselves.

His methods, to be sure, are unorthodox; he only works under the cover of night, and leaves clues on his website as to where fans can find his pieces. Though they're technically illegal, they've sold for hundreds of thousands, or even millions, of dollars. His latest stunt has been on the streets of New York City, employing a new work of art every day throughout the entire month of October.

Role: Co-CEOs and co-founders of Birchbox

Age: Both 30

Birchbox is "Netflix for beauty." Katie Beauchamp and Hayley Barna have earned a ton of buzz over the innovative idea and exponential growth of their curated personal care delivery company, Birchbox. For $10 per month, members receive a little box in the mail filled with high-end beauty samples, curated based on each user's beauty profile.

Last year the two launched Birchbox Man, branching out into another eager consumer demographic.

The former Harvard Business School classmates dreamed up the idea to fill a void in women's shopping. Fashion e-commerce had taken off, but the online market for beauty hadn't been cracked yet, according to Beauchamp. Birchbox has since raised $11.9 million in funding and boasts 400,000 subscribers.

Role: Co-CEOs of Warby Parker

Age: Both 33

Warby Parker, a new eyeglass company based in New York, is expanding all over the U.S. and taking on Luxottica, the behemoth that currently has a monopoly on the majority of the world's eyewear. But Warby Parker's model is different: They sell glasses quickly, easily, and directly online.

The company lets you choose up to five different frames through their Home Try-on program, which they ship to your door so you can see which one you like best without having to imagine what it will look like on your face. All their models are stylish, and all cost the same flat $95.

The company also provides a pair of glasses to someone in need with every pair sold. Warby has grown exponentially since it began, famously starting with a 500 percent increase in growth in their first year. Recently, Warby Parker gained an investor in J. Crew CEO Mickey Drexler, who has been giving its founders advice on expanding into retail.

Role: Author and investment advisor of Fusion Analytics Investment Partners

Age: 36

Joshua Brown has earned a reputation as Wall Street's whistleblower, spending years writing about the lack of transparency and conflicts of interest in the financial industry. His popular blog, The Reformed Broker, and his book, "Backstage Wall Street," serve as an insider's guide to knowing whom to trust and how to maximize investments.

Brown hopes to change the culture by exposing the tricks of the trade, which he learned during his first decade in the Financial District as a stockbroker.

This fall, he launched his own independent investment advisory, Ritholtz Wealth Management, that manages more than $100 million in assets. He and co-founder Barry Ritholtz consider the new venture a chance to manage money with integrity.

Role: Chef and owner of the Momofuku Restaurant Group

Age: 36

The Korean-American chef is known for his disruptive cuisine and attitude — about food, and things in general. David Chang, who sustained himself on cheap instant ramen throughout high school and college, used $130,000 in startup capital from his father and friends and built an empire rooted in his appreciation for the culinary art of noodle-making.

Since 2004, his New York City-based restaurants — Momofuku Noodle Bar, Momofuku Ssäam Bar, Momofuku Ko, Milk Bar, and Má Pêche — as well as international franchises, earned him the 2013 Outstanding Chef award from the James Beard Foundation, not to mention a cult following.

Role: CEO and co-founder of Airbnb

Age: 32

Airbnb is an online community marketplace that allows people to rent their homes or rooms to guests, giving travelers cheaper, homier accommodations for a fraction of hotel rates. For hosts, it can be a secondary source of income — one Airbnb user even bought a house with the $50,000 he made by renting his place out on the site.

Airbnb has raised $120 million in funding to date, despite New York State legal hurdles that prevent New Yorkers from renting their homes.

Founded in 2008 after graduating from the Rhode Island School of Design, Brian Chesky drives the company's vision and strategy as it expands into 192 countries.

Role: President of Cinnabon

Age: 35

Cinnabon, which was once seen as just a food kiosk in malls, is now becoming a household brand name thanks to Kat Cole.

The former Hooters waitress worked her way up to become president of Cinnabon before the age of 35, and is credited with taking its indulgent creations to grocery store shelves and fast food chains like Taco Bell. Licensing now accounts for more than half the chain’s revenue, and this year global sales will reach $1 billion.

Last fall she became the youngest executive to appear on "Undercover Boss," a hidden camera show where CEOs and head-honchos visit their company's locations to witness firsthand employee morale and the working environment.

Role: Financial Assistant to the Chairman at Berkshire Hathaway

Age: 29

Warren Buffett almost never hires new people, but he hired Cool and gave her a lot of responsibility — way more than most other new graduates who enter the financial industry.

Tracy Britt Cool, who hails from a farm in Kansas and graduated from Harvard Business School in 2009, quickly got on the fast track to success when she found a teacher and mentor in Buffett. She's currently the chairman of four Berkshire-owned companies — Benjamin Moore, Johns Manville, Larson-Juhl, and Oriental Trading — and on the board of H.J. Heinz. Buffett has even hinted that, one day, she might succeed him as Chief Investment Officer of Berkshire Hathaway.

Those are some big shoes to fill, but for someone Buffett has called a "blotter for learning," maybe not too big for Cool.

Role: Executive Vice President of Baseball Operations for the Tampa Bay Rays

Age: 36

Andrew Friedman appears to live by the mantra, "change is good." Since leaving his analyst job in the investment and private equity industry in 2003, he has shepherded the Tampa Bay Rays in an absurd number of turnovers.

He's traded established Major League talent for highly regarded prospects on a shoestring budget, handpicking players each off-season who can compete with the league's big-spending teams.

His risks have paid off, and the Rays have recorded six straight winning seasons, having advanced to the postseason in four of those six.

Role: Chief Digital Officer for the City of New York

Age: 30

Since her appointment in 2011, Rachel Sterne Haot has been creating new and innovative ways to communicate with the city's 8 million-plus residents, starting with the Made in New York digital roadmap, a lengthy plan, report, and interactive website that allows you to search for jobs and startups in New York that are hiring. She's also responsible for launching the city's first official hackathon.

She's been very active post-Hurricane Sandy about making sure that the New York tech world — much of which is located in areas affected by the storm — is more resilient and better prepared should something like this happen again.

Her schedule has been very full this year, with plans for the CornellNYC tech campus on Roosevelt Island, and the unveiling of a new Web hub called We Are Made In NY, a site that will make government services easier to navigate and put to better use.

Role: Curator of Mammals at the Smithsonian National Museum of Natural History

Age: 34

Though he's still in the beginning of his career, Kristofer Helgen has already discovered approximately 100 species of mammals around the world that were previously unknown to science, including the newly-discovered carnivorous mammal, the olinguito.

The olinguito made headlines not just because many people mistook it for the already-known olingo, but because finding a new, carnivorous mammal is extremely rare. Helgen was the one who led the discovery, which took 13 years, and actually started out as a study to fully describe the olingo.

It was at the Chicago Field Museum that Helgen found pelts identified as those of the olingo, though they seemed different to Helgen. Upon analyzing the teeth and general anatomy of the associated skulls, Helgen realized that it was an entirely new species.

Role: Founders of Vine

Age: 27 (Dom) and 29 (Rus and Colin)

Dom Hofmann, Rus Yusupov, and Colin Kroll launched the six-second, looping video-editing app in January as a way to easily cut video shots together. It sold to Twitter just six months later.

The first video-focused social network continues to evolve in applications beyond its founders' expectations. In April, it emerged as a national news tool when a video of the explosion at the Boston Marathon went viral online. The media called it Vine's "Tahir Square moment."

It's branching into the advertising and entertainment worlds as well. Freelance stop-motion animators are recruited to create Vine videos for ad campaigns at Nike, BMW, GE, MTV, Virgin Mobile, and more.

Role: CEO of Zappos

Age: 39

In addition to being the CEO of the popular online shoe and accessories company Zappos.com, which is based in Las Vegas, Tony Hsieh is determined to do some good for his area: He's working to revitalize downtown Las Vegas by investing $350 million of his own money into the city through his lofty Downtown Project.

Hsieh's goal is to make Vegas the smartest, most “community-minded” city in the world — a lofty goal, for a city that is run by casino tourism and where few people want to live, especially after the housing crash. But Hsieh has already started his car- and bike-sharing program with the purchase of 100 Tesla Model S cars, and on its way are a 150-seat theater and an outdoor mall made of repurposed shipping containers called the Downtown Container Park. Tech startups are very happy about the change in the city.

"One of our goals is to have everything you need to live, work, and play within walking distance," Hsieh told Inc. in an email.

Role: CEO of Qcue

Age: 31

Barry Kahn is the brain behind sports startup Qcue, a software company that helps teams gauge interest in a game and analyze sales projections, so that they can adjust ticket prices accordingly (and earn up to 30 percent in incremental revenue over a season).

More than 40 teams across Major League Baseball, Major League Soccer, the NBA, and collegiate organizations take advantage of Qcue, giving it the largest roster in the "dynamic ticketing" industry.

Plus, fans are increasingly accepting market value pricing as a guarantee their ticket is worth the buck.

Role: CEO of Uber

Age: 37

Uber is a revolutionary transportation service that lets people easily get transportation whenever they need it — simply ping the mobile app to summon a driver whenever you need one. Based on this simple yet revolutionary idea, the company grew rapidly and already raised $35 billion this year.

Yes, billion. With a "b." Private equity firm TPG purchased 775,092 shares at $114.03 apiece for a near $90 million investment, while Google Ventures and Benchmark made up much of the rest.

Uber has been coming up with a number of new, short-term marketing ploys as well, but ones that could easily be implemented for the long-term in the near future. Travis Kalanick's team has done on-demand ice cream trucks this past summer, which delivered ice cream to those who hailed the truck on their phones; on-demand roses on Valentine's day; helicopter rides to the Hamptons during Fourth of July weekend; and on-demand barbecue in Texas.

Role: CEO of Tumblr

Age: 27

David Karp created the short-form blogging platform in reaction to Facebook, which he regards as "insanely restrictive." Tumblr, the unofficial home of the GIF, boasts 300 million monthly unique visitors and adds 900 posts per second, according to a press release by Marissa Mayer.

The recent Williamsburg transplant sold his company to Yahoo for $1.1 billion earlier this year. Not bad for a high school dropout.

Karp is dead-set on keeping Tumblr in New York — a city less regarded as an incubator for startups — because he sees the company as a reflection of its rich creativity: "That is so much of what Tumblr is, a media network, a home for tens of millions of creators."

Role: Cell phone gadget inventor

Age: 18

Like the typical teenager, Eesha Khare was tired of her phone battery constantly dying on her; but unlike the typical teenager, she did something about it. That's how she conceived of — and then built — a battery-sized portable energy storage device.

The supercapacitor can charge a cell phone in 20 to 30 seconds. Its special nanostructure, which enables a lot greater energy per unit volume, gives it a breakthrough rate that sets her device apart from its marketplace competitors.

This year her invention won her the Intel Foundation Young Scientist Award. She is using the $50,000 prize money to pay for tuition as a freshman at Harvard University.

Role: Self-taught prosthetician

Age: 17

Easton LaChappelle made his first mechanical hand out of LEGOs, fishing wire, and surgical tubing at the age of 14, and kept improving the design with 3D-printed parts. An encounter with a seven-year-old girl at a science fair, whose prosthetic arm costs $80,000 (and would need to be replaced when she outgrew it), inspired him to turn his prototype into a real, affordable technology.

Not only were his designs amazing, but his young age, combined with the fact that everything he knew about robotics was self-taught, got him a lot of buzz.

His latest prosthetic, which controls movement via brainwave measurements, costs under $400 and could change the lives of amputees. Everyone is excited about this innovation, from the armed forces, who plan to use the prosthetic to carry out bomb defusing missions, to Heineken, which has already bought thousands of arms from LaChappelle to serve beer at bars.

Role: Co-founders of The American Reader

Age: 25, 26

Uzoamaka Maduka and Jac Mullen, both Princeton alumni, founded The American Reader, a high-level, intellectual print and digital literary magazine that looks like it's run by veteran literary critics. Its mission is "inspiring literary and critical conversation among a new generation of readers, and restoring literature to its proper place in the American cultural discourse."

Think of it like The New Yorker for millennials: Its digestible, digital format gives it an edge among younger readers, but its paper format still makes it accessible to older readers. The two have received a lot of media attention since founding the magazine in late 2011 after recurring conversations about the collapse of literature. They wanted a magazine that didn't just focus on the literary scene, but on literature, and in a way that would capture the attention of a millennial audience.

Role: CEO of GrubHub Seamless

Age: 38

When GrubHub and Seamless, two of the most popular food delivery services, merged in May, GrubHub founder and CEO Matt Maloney was named the CEO of the new, merged company. The two companies had previously been rivals, with Seamless more popular in New York and GrubHub the favorite in the Midwest, but they shared a common enemy (paper menus), and as everyone knows, the enemy of your enemy is your friend.

Maloney was a student at the University of Chicago when he co-founded GrubHub, and in doing so revolutionized the way people order takeout or delivery by making the process both paperless and phone-less, taking the hassle out of getting takeout.

As a food delivery conglomerate, GrubHub Seamless now reaches a combined 500 cities and works with more than 20,000 restaurants.

Role: CEO of Yahoo

Age: 38

Marissa Mayer is one of the youngest CEOs of a Fortune 500 company, and in little more than a year she's managed to get the company’s stock price up 100 percent, make engineers want to work for Yahoo again, and overhaul the company's email system with a cleaner design and fewer ads.

And most recently, she wooed David Karp into selling Tumblr to Yahoo for $1.1 billion, a move which will gain the tech giant a boatload of the younger users that Tumblr has access to.

Mayer's been strategic and calculated in her time as CEO so far, which has not only saved the company but boosted employee morale and made it a better place to work.

Role: Founder and CEO of Marcato Capital Management

Age: 37

Mick McGuire's $2.2 billion hedge fund was named U.S. equity hedge fund of the year by Absolute Return Alpha, and McGuire himself was named the emerging fund manager of the year by Institutional Investor.

McGuire, who used to work for Pershing Square Capital Management and has been labeled Bill Ackman's protégé, started his hedge fund in 2010 with financial backing from Blackstone and, so far this year, his fund is up 17.1 percent according to Reuters.

For someone so young, McGuire has a lot of power and influence on the market: Last month he spoke about United Rentals, a company in which his firm has a 4.7% stake, claiming that fresh construction will give the company a huge boost. Within 24 hours, United Rentals share prices had climbed almost three percent, showing that when McGuire speaks, people take him seriously.

Role: President of Visa

Age: 38

The former head of JPMorgan's consumer banking division had risen to oversee 76,000 employees and subsequently became the youngest member of the bank's executive committee.

Ryan McInerney was famous for his radical approach to improving customer service, even going so far one time as to gather all bank district managers in one room and play customers' complaints over a loudspeaker for an hour and a half. It was definitely effective, because JPMorgan customer satisfaction rose in the rankings by the time he left the company.

McInerney was appointed the new President of Visa in May, and people are excited to see what he will do in his new position.

Role: Fashion blogger known as "The Man Repeller"

Age: 24

Leandra Medine's blog, The Man Repeller, is founded on the idea that men hate the fashion trends that women love. She's been named as one of the most influential bloggers by Forbes and Time, with nearly 430,000 loyal followers on Instagram.

Medine started her blog in April 2010 when a friend suggested that the reason the men she dated didn't want to be her boyfriend was because of the way she dressed.

Not only is the concept behind her blog quite novel — that it's better to dress with style, even if that style "repels" — but Medine coined the phrase "arm party," meaning to wear a bunch of different bracelets at once, showing that she's creating her own fashion trends, not just writing about others.

Role: CEO and co-founder of The Muse

Age: 27

Kathryn Minshew's website helps more than 3 million users discover new career paths, find great companies through innovative hiring profiles, and get personalized job recommendations.

Earlier this year Minshew expanded and rebranded the company from The Daily Muse, a career site for professional women, to The Muse, a career site for everyone. With amped-up career advice and a beautiful, new jobs board, each company page looks like a resume inviting you to apply, with digital features like office tours, staff profiles, and their Twitter and Facebook feeds. It gives a wonderfully boxed-and-bowed overview of the company culture and direction, all in one place.

In 2011 she was working on a different careers-related site when she and the three other co-founders differed on how it should be run, so Minshew opted for a "do-over" and created her own site.

"It was painful, but being forced to start over was a unique sort of gift," Minshew told Entrepreneur, "because having been through a lot together, the team comes out of it with the confidence that nothing is going to stop us."

Role: CEO and co-founder of Fitbit

Age: 37

This Harvard dropout and serial entrepreneur is on a mission to instrument the human body and use data to motivate people to live healthier lives. The former cross-country runner and avid swimmer realized that years of startup life had not been kind to his body, so he created the Fitbit, the first wireless wearable fitness device in the notoriously hard-to-crack consumer electronics market.

This summer Fitbit raised $43 million in funding and will use the capital to release new products like the Force, a wristband which comes out this month and tracks steps taken, distance traveled, calories burned, stairs climbed, and sleep patterns. It also syncs with the iPhone's iOS 7 to alert you to incoming calls.

Role: CEO and founder of BuzzFeed

Age: 39

After co-founding The Huffington Post in 2005, Jonah Peretti launched BuzzFeed in 2006 as an experimental lab that focused on tracking viral content. Under the MIT grad's fierce leadership, BuzzFeed — known for its list-based approach to journalism — has increased its readership to 85 million monthly unique visitors.

Since hiring POLITICO's Ben Smith during the presidential election, Peretti has put BuzzFeed on the map as a legit source for hard news and politics — and not just cat memes. In addition to expanding its more long-form content, BuzzFeed is developing two teams of international news correspondents and investigative journalists.

"And we've become profitable while making these investments," Peretti recently boasted to Wired. "The business case is simple: Despite a growing hole left by the decline of print media, the public still wants news, entertainment, and great storytelling."

Role: CEO of H&M

Age: 38

Karl Johan Persson shook up the fashion retail industry when he boldly chose to include plus-sized models in the summer swimsuit campaign. He said that many of the models the brand has featured in the past were too thin, leading to speculation that other brands could follow his example.

Persson has filled a number of roles at H&M since 2006, and continues to evolve the brand into a leader of sustainability. H&M is the biggest user of organic cotton in the world, the first fashion retailer to launch a global system to reuse old clothes, and a WWF partner in setting new standards for water stewardship.

Persson — who said a great majority of his own wardrobe is from H&M — hopes it will be designated a fair trade brand in a couple years.

Role: Instagram and Vine animator

Age: 23

Khoa Phan's first Vine video was like any other: six seconds of brewing a cup of Keurig-made coffee. But Phan's second Vine, a stop-motion short, was the one that put him on the map as an innovator when it comes to social media and, eventually, new and original ways to advertise a brand.

Phan now works with Peanuts, MTV, and other brands to create stop-motion animation Vine videos as marketing tools. He has more than 17,000 users following his Vines, which have also attracted the attention of the Tribeca Film Festival, earning him two nominations in the Animate category.

Role: Managing partner and founder of Millennial Branding

Age: 29

Dan Schawbel is an "ambassador to Gen-Y" as the founder and managing partner of research and consulting firm Millennial Branding.

He's one of the first and foremost experts on millennials as consumers — their likes, dislikes, and habits — and he engages with companies to understand the emerging young professional to make the companies more profitable and grow market share.

His book "Promote Yourself: The New Rules for Career Success," which is like the new Millennial Branding bible, came out last month and immediately made the NYT best-seller list.

Role: Founder of pop-up shop STORY

Age: 37

Rachel Shechtman has embraced the unique concept of the pop-up shop and taken it one step further: Hers is a pop-up shop with a permanent storefront in New York that completely overhauls what it sells every six weeks. Shechtman describes her business as "a dating service using storytelling as the matchmaker between brands and consumers."

She's made a huge effort to integrate e-commerce, along with the big brands, into STORY, so long as it all follows the theme the shop is going for during those six weeks. It's really the first store of its kind anywhere.

For a shop that reinvents itself every month and a half, Shechtman's is doing a great deal of business, even showing a profit after the first year.

Role: Founder of FiveThirtyEight

Age: 35

Nate Silver caused a political riot when he correctly predicted the November 2012 presidential election outcomes in every state . .. for the second election in a row.

It's a feat that either requires a bit of clairvoyance, or a great head for math, which Silver has. He makes his predictions using an advanced metric he created that averages hundreds of state polls and takes other factors, like economic data, into account.

Silver and the political and statistical website he founded, FiveThirtyEight, were previously contracted by the New York times, but it was announced in July that he would be moving from The Times to ESPN, and that FiveThirtyEight would be going with him. Silver plans to have a number of focus topics beyond politics and sports, including weather, education, and economics.

Role: Founder of Instagram

Age: 29

Kevin Systrom first got his hands in the startup scene when he interned for a company called Odeo — a company better known now as Twitter.

In launching Instagram, Systrom introduced a new concept to the world of social media: a network that was based on images being used to narrate our day-to-day lives. He brought the idea of "a picture's worth a thousand words" to life, and within a month the app had a million users, making it one of the most popular, if not THE most popular, and widely-used photo apps and visual social networks ever.

Just months ago Systrom unveiled Instagram video, but that's not the only new development — he hopes to start selling display ads within the next year, putting it on the right track for a lot of revenue.

Role: Professor at Carnegie Mellon University, and creator of Duolingo

Age: 33

The Carnegie Mellon University professor is responsible for making learning a new language cheaper and more efficient than other means of learning with his language learning app, Duolingo.

Available in six languages, a study of Duolingo, conducted by the City University of New York and the University of South Carolina, revealed that using the app for just 34 hours can yield the same reading and writing ability of a first-year college semester — 20 fewer hours than it would take to learn from Rosetta Stone.

When the app came out for iPhone last year, it quickly became one of the top education apps in the app store; it was just released for Android this past spring, and is the number one free education app in the Google Play store.

Luis Von Ahn is also proving that his app is good for more than just language learning; he's partnered with BuzzFeed to deliver their content in other languages and grow readership internationally.

Role: Founder and CEO of LearnVest.com

Age: 30

Alexa Von Tobel, a former Morgan Stanley trader and Harvard Business School drop-out, calls her company "Weight Watchers for money." She's built an easy-to-follow financial planner that empowers people — particularly women — to take control of their personal spending and reach their goals.

Its innovative, cross-platform design and editorial content steeped in expert advice transformed the perception of budgeting as complicated and chore-like.

When not running LearnVest, she shares her wealth of financial knowledge as a contributing writer for Inc. magazine and Huffington Post.

Role: CEO and founder of NaugaNeedles

Age: 37

NaugaNeedles is making huge strides in nano-technology and nano-research.

"We're making tools that enable researchers to do things in nano-scale," Dr. Mehdi Yazdanpanah said in an interview with BI. His company's "nano-needles" — incredibly small metal wires with sharp points — are being used by researchers to manipulate, probe, and measure things on a microscopic level like they've never been able to do before.

The whole thing started when Dr. Mehdi Yazdanpanah discovered, in a University of Louisville lab, that silver and gallium react with each other at room temperature, forming a nano-needle-like structure. From there he figured out how to make the needles form individually, and has been selling them to scientists and researchers all over the world.

Role: CEO of Facebook

Age: 29

Last year, under the guidance of CEO Mark Zuckerberg, Facebook hit a major social media milestone by attaining 1 billion users, with almost 699 million of them active.

The social media site strives to connect all of its users with features like graph search, which launched earlier this year and allows people to search for other users they know, or might know, based on the company's existing user data.

But Zuckerberg realizes that not everyone in the world has Internet access, which is why he launched an organization called Internet.org last month, with the goal of bringing the web to the parts of the world that lack it.

Making matters even better, Facebook stock prices have risen by nearly 30 percent in recent months, due in part to the company's visible improvements in mobile.

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