Automattic, the parent of blog platform WordPress, unveiled BuddyPress Thursday, a platform built on top of WordPress designed to let its users build social networks around their sites. The framework includes private-messaging features, profile setups and activity streams, all of which can be customized.

SEE ALSO: Yahoo Spins Off Blo.gs To Automattic

Automattic, which has raised at least $30 million in venture funding, has been steadily adding to its properties. It bought the blo.gs pinging and blog trackback service from Yahoo (NSDQ: YHOO) earlier this month. And in October it purchased the PollDaddy, which it has since embedded into the WordPress editor.

There are other easy ways to create social networks on the web too (Think Ning). But BuddyPress lets users set up a social network on their own existing site, rather than have to head elsewhere. “There’s been a dearth of Open Source tools that enable the social web,” says Automattic’s Matt Mullenweg in blog post. “I don’t think BuddyPress will be something you use instead of your existing social networks… but if you wanted to start something new maybe with more control, friendlier terms of service, or just something customized and tweaked to fit into your existing site, then BuddyPress is a great framework.”