eBay's StumbleUpon subsidiary announced it has reached a milestone of five million registered users and almost five billion "stumbles" since its debut in the fall of 2001, with over one billion stumbles to date in 2008.

Michael Buhr, General Manager of StumbleUpon, said, "People are looking beyond traditional search for better ways to sift through the vast amounts of content online and discover what is interesting, useful and relevant to them."

A stumble equates to a Web site delivered to a user when they press the Stumble button on the StumbleUpon toolbar. According to the company's press release, "With StumbleUpon, people are tapping the wisdom of crowds to get personal recommendations of great Web sites and Web content that matches their needs and interests and, more importantly, content they would not have found via a traditional search engine." The company was founded in 2001, and eBay acquired the company in May 2007.

http://www.stumbleupon.com