I have no idea what my mom's cell phone number is. I don't think I've ever known the phone number of a girlfriend. Why would I? You probably don't either! Contact lists killed them. But web service Go800 wants to skip the whole number thing entirely, letting you hit people via their Twitter handle to connect a call.
It works fairly simply. Register an account with Go800, authenticate your Twitter account, and then anyone who shoots a text with your tweetie name to 46800 triggers a phone call. Both parties answer, and then kaboom, you're on the phone—no dialing required.
There are a few caveats. Texting in a Twitter name isn't as snappy as just hitting someone's name on a contact list—and the connection is subject to whatever delays the SMS gods feel like imposing at that particular moment. When I tested out the service, it took a few tries to get it working. You'll also only be able to use the service, it should go without saying, unless the people in your life have signed up for it. So it'll only be as useful as it is popular.
Stoll, Go800 has some nice extra touches—any privacy worries (ie, every pervert on Twitter being able to call you) covered. You can create a white list if you please. And a smartphone app is on the way that'll let you bypass the SMS process entirely, letting you "dial" Twitter names directly.
It's a neat concept, and probably more than a novelty. Phone numbers really are obsolete—and we're increasingly knowing each other by @names and Facebook logins, rather than a string of digits. At this point, we probably know way more people by their online monikers than by their phone number—if you know any numbers at all. [Go800]