It took 16 years for Salesforce to finally become part of this exclusive list of America's largest companies

Salesforce may already be one of the most powerful companies in San Francisco, but in the rest of world, it's still working its way up to becoming a mainstream brand.

And this week, it took another step forward by setting a new milestone in its 16-year history: it became part of the Fortune 500 list for the first time.

Being part of the Fortune 500, Fortune Magazine's annual list of America's largest companies, is a big badge of honor for most businesses.

Companies are ranked by their size of revenue, so making the list is a sign that you've made it to the grand stage.

As Salesforce CEO Marc Benioff put it: "This is a huge milestone for Salesforce, and a great validation of our dedication to the cloud and customer success, as well as the trust our customers place in us."

For people in San Francisco and the technology sector, however, this may come as a bit of a surprise. Salesforce is the largest employer in San Francisco and its big annual conference, Dreamforce, attracts so many people that you would think Salesforce had made the list a long time ago. Not to mention the influence its larger-than-life CEO Marc Benioff exerts on all kinds of issues, from business and politics, to social and gender problems.

By comparison, Facebook was the fastest company to ever join the Fortune 500 list in 2012, less than a year after going public. Before that, it was Google, who took 16 months post-IPO to make the list. Salesforce went public in 2004.

Salesforce was ranked at #483 this year, but if it weren't for its subscription model and certain accounting rules, it could have ranked even higher. Last year, it had $5.4 billion in sales, but if you include all the deferred and unbilled revenue it couldn't account for in its last fiscal year, Salesforce's total sales could have been closer to $9 billion.

Regardless, Salesforce will likely keep going up the ranks as it recognizes more of that unbilled revenue under contract and continues to expand internationally. According to Benioff, 90% of all enterprise software is still bought in just 7 countries worldwide.