Microsoft Portrait
When did it launch? Late 1990s
What did it do? Portrait was, as Microsoft described it, a "very low bit rate video conferencing software" that came before Skype (which Microsoft later acquired for $8.5 billion) and FaceTime.
How big is the idea now? Very. Skype is seeing three billion minutes of calls per day, according to Microsoft.
Terraserver
When did it launch? 1997
What did it do? Terraserver was, essentially, Google Earth before Google thought of it. You could see your house, your neighbourhood, or a place you've never been before via satellite imagery. Terraserver was killed in 1999.
How big is the idea now? Google Maps is one of the most used apps in the world, behind only Facebook, YouTube, and other Google services. The app reportedly had over 65 million downloads in 2014.
MSN
When did it launch? 1995
What did it do? MSN Messenger was the first social network. Almost 10 years before Mark Zuckerberg built Facebook, Microsoft customers were IMing each other, setting a status message (which would later inspire Twitter), and various other social networky things. MSN was shuttered in 2012.
How big is the idea now? Facebook has over 1.5 billion users while Twitter has over 400 million. Chat apps, such as WhatsApp and WeChat, have 900 million and 650 million users, respectively.
Windows Mobile
When did it launch? 2000
What did it do? Windows Mobile was the first mass market smartphone operating system that could be used on a high-end device, many of which came from HTC. Windows Mobile included an app store, a browser, and touch screen support. Microsoft stopped supporting Windows Mobile upon the release of Windows Phone 7 in 2012.
How big is the idea now? Inconceivably big. Apple's iPhone business brought in over $150 billion (£100 billion) in 2015. Google's Android is used by 1 in 5 people on Earth. Samsung has made tens of billions from its Galaxy range of phones.
The tablet PC in 2002
When did it launch? 2002
What did it do? Microsoft's first tablet was a desktop PC with a touchscreen. It could run Windows XP apps and users could interact with a stylus. Bill Gates event showed it off onstage. Microsoft never officially shuttered the project — as evidenced by the Surface — but no new tablets were made between 2003 and 2012.
How big is the idea now? Apple's iPad business generates $5 billion (£3.2 billion) every quarter and has enabled the company access to enterprise customers who would traditionally only use Windows.
Microsoft Mail
When did it launch? 1991
What did it do? Microsoft Mail allowed for the sending and receiving of messages across local networks. This was the first form of email, albeit a rudimentary take. Microsoft shuttered Mail in the late 1990s.
How big is the idea now? Almost everyone on the internet has an email account. Outlook alone has more than 400 million users, according to Microsoft. Google Mail has around 450 million users.
Microsoft Bob
When did it launch? 1995
What did it do? Microsoft Bob was a graphical user interface for Windows 3.1, which launched in 1992, and Windows 95, which launched in 1995. It provided an easy-to-understand interface that made Windows, and PCs, accessible to the masses. It never took off, however.
Prior to Bob, Windows PCs had used command line interfaces that were essentially text on a screen.
How big is the idea now? Every interaction we make with the more than 1.5 billion devices in the world (as of late 2013) is through a graphical user interface.
The Timex DataLink smartwatch
When did it launch? 1994
What did it do? The Timex DataLink was co-developed by Microsoft and Timex as a wearable alternative to personal data assistants. The watches, which bore Microsoft's logo, were used by NASA for space travel but never took off commercially.
How big is the idea now? Smartwatches, lead by Apple, are just starting to become a commercial success product. According to analysts, Apple has sold more than 7 million units since April.
MSN TV
When did it launch? 1996
What did it do? Microsoft acquired WebTV Networks in 1995 for $425 million (£280 million) and launched MSN TV, the first smart TV that was internet connected and could be used for browsing the internet. Microsoft shut MSN TV down in 2013.
How big is the idea now? Smart TVs are big business for Samsung, LG, and Apple, who recently launched an all-new Apple TV. Samsung has sold over 75 million TVs since 2009.
Microsoft Courier
When did it launch? Never.
What did it do? Courier was first revealed in 2008 by the press before being killed by Microsoft in 2010, the same year Apple launched the iPad. The device was an early version of what would become the Surface line of tablets, with an in-built camera and a "folding" display.
How big is the idea now? Microsoft's Surface business brings in around $888 million (£580 million) per quarter, far less than Apple's $5 billion (£3.2 billion).
Zune Music Pass
When did it launch? 2010
What did it do? Zune Music Pass (now Groove Music) launched alongside the Zune series of music players, offering unlimited access to a catalogue of streaming songs for $9.99 (£9.99 in the UK) a month. Apple launched Music, a streaming service that allows access to a catalogue of songs for $9.99 (£9.99 in the UK), in 2015.
How big is the idea now? Spotify, Apple, Google, and Pandora are all going head-to-head in the music streaming space, offering more and more songs for less and less money. Spotify has 75 million users, of which 20 million pay, while Apple pay reportedly has around 15 million, gathered in less than six months.