button that, when pushed, opened a semi-random website or video that matched the user's interests, similar to a random web search engine.

These investors included Tim Ferriss, Ram Shriram of Google, Mitch Kapor of Mozilla Foundation, First Round Capital and Ron Conway and the company was then valued at approximately $4 million.

[6] In April 2007, StumbleUpon launched the StumbleThru service, allowing users of the toolbar to stumble within websites such as those of Flickr, MySpace, Wikipedia, YouTube, BBC, CNN, PBS, The Onion, and Phys.org.

[13] In March 2009, StumbleUpon launched Su.pr, a URL shortening service, primarily to link to Twitter and Facebook statuses and updates.

[17] In April 2009, Garrett Camp, Geoff Smith and other investors including Ram Shriram re-acquired the company for $29 million.

[18][19][20] In 2009, StumbleUpon drove more traffic to webpages than any other social media site in the US, including Facebook, YouTube, Twitter, Digg, Reddit, and Pinterest.

[35] On September 24, 2013, StumbleUpon acquired 5by, a mobile app founded by Greg Isenberg that recommends videos based on user interests.

[40] StumbleUpon was shut down in June 2018 and its accounts were transitioned to Mix.com, another content discovery venture built in part through Camp's studio startup company, Expa.