Yahoo has rolled out its new social networking website called “Mash” which, according to reports, has the feel of Facebook, a touch of MySpace and a Twitter-like messaging feature.

Computerworld, which is among the earliest to break the story, reported that Mash, which was still in beta version, is now available by invitation only.

What Mash has that others don’t is a feature that allows users to make starter profiles for their friends and to leave their own profiles open to let other “trusted” users add content.

Computerworld quoted Michael Arrington, a beta user of the Mash network who blogs at TechCrunch, as noting that Mash allows users to load modules like Flickr Real Simple Syndication and blog applications into their profile pages.

“While profile pages appear to have a pretty consistent structural layout (like Facebook), users can customize the design of their pages by changing colors and inserting background images (like MySpace),” he said.

Mash also has a feature called Pulse, which are “Twitter-like messages” reporting all the activities a user’s friends make on the site, he added.

Ever wonder how many social networking sites are there? There are dozens of them, according to Wikipedia.