It hasn’t sustained the massive buzz it got when it first launched, but Flock, the browser that specializes in social networking, has raised a big $15 million fourth round led by Fidelity Ventures. Past backers of the Redwood City, CA-based company Bessemer Venture Partners, Catamount Ventures and Shasta Ventures also participated. The total raise of its previous three rounds hasn’t been announced officially, though it’s been reported in the $12-$13 million range, and it notes in this release that this one is bigger than all three combined, so that would make sense. The browser itself is based on the open source Mozilla Firefox code, and it has been, at times, criticized as basically being Firefox with certain social plugins pre-installed. It also includes a feed reader and a blog post editor.

SEE ALSO: Flock Browser Gets More Funding

This continues a steady stream of late stage fundings we’ve been seeing, as well as the heavy participation from Fidelity. It participated in both Wetpaint’s latest round and the big $50 million round or Slide.  It’s hard to say how the company is really doing: It says the user base is up by 250 percent since the beginning of the year and that revenue is up 400 percent since then (though they don’t specify what prior period they’re comparing themselves to). Presumably, most of its revenue, like with Firefox, comes through the searchbar. Release.