In the past 16 months, the personalized discovery engine has doubled its user base. It now has more than 20 million registered users who “stumble” (click a button to load a webpage the site has picked out based on users’ preferences and behavior) more than 1 billion web pages every month.
StumbleUpon‘s growth spurt coincides with a hiring spree — it doubled its number of employees from 40 to 80 — and aggressively launched its first mobile apps. Since August 2010, the company has launched iPhone, iPad and Android apps, with help from a $17 million round of funding that closed in March.
“It’s only been a year and we’ve gone from really just being at your desk to a whole new group of people who only use it on their phones. They don’t even know there’s a website,” StumbleUpon CEO Garrett Camp told Mashable. “Next year we’re going to be as much on mobile as we are [on desktop].”
StumbleUpon’s 20 million users still don’t make it quite comparable to other popular social sites that it might be tempting to group it with. Tumblr has 31 million blogs; LinkedIn has more than 100 million users; Twitter has 200 million registered users; and Facebook has 800 million users.
But it’s gaining steam that could someday put it in that group. The next step, Camp says, will be international expansion.
“We’re just exploring it now,” he says. “Hopefully next year.”
Click the chart to enlarge.