Redwood City, Calif. - Flock, the developer of a social Web browser, announced on Thursday that it has completed a $15 million fourth round of venture funding, led by Fidelity Ventures.

Previous backers Bessemer Venture Partners, Catamount Ventures and Shasta Ventures also participated.

Founded in 2005, Redwood City, Calif.-based Flock offers a free downloadable application for the Firefox browser that simplifies and extends the use of social and Web-based applications.

The company said its user base has increased by more than 250% while its revenue has risen over 400% since January 2008.

The funds will be used for research and development, marketing and expansion into new global markets.

Related Links:
http://biz.yahoo.com/bw/080522/20080522005246.html?.v=1

http://www.flock.com