It's an interesting idea technically, though socially people, in the main, find it difficult to pick up the phone and talk to someone they know nothing about (beyond a few tags and a name).
Even showing a Gravatar and making it mandatory to provide a homepage URL or Twitter link would allow users to do a quick bit of "research" on someone they want to call in order to feel more comfortable and to build up a little virtual rapport ahead of time.
Seconded. I'd feel a lot more comfortable chatting people up with questions if I had a peek into the projects they've done before.
And, knowing I'd like to have people call me up with their projects, it's to everyone's advantage to bring the barrier to entry down as much as reasonably possible.
Even showing a Gravatar and making it mandatory to provide a homepage URL or Twitter link would allow users to do a quick bit of "research" on someone they want to call in order to feel more comfortable and to build up a little virtual rapport ahead of time.