With the emergence on VoIP as a popular mainstream communications method, but with various protocols, servers and clients, as well as a plethora of instant messaging and email systems, it would be nice to have a "Whitepages" site for these details.
Free to list and browse, with a method to avoid mass-harvesting of usernames/email addresses.
Then if I need to contact Bob Smith, I could check to see if he uses a VoIP service that I could potentially use to contact him for free rather than an expensive telephone call.
Is this idea a goer, or just another lame duck waiting for my neighbour to enter the maimai with a 12 gauge?