Facebook gets groups, when will twitter?

It wasn’t part of the new facebook, but recently facebook enabled you to group your friends into different lists.  This is a natural part of someone with a growing list of friends that they may want to keep track of.

Now I don’t even have that many people I follow on twitter just 150 (nice round number, shame to have to add more) but still I wouldn’t mind being able to sort them, and in theory I may want to just message some of them about some events, say some local stuff that is happening here in Bloomington.

This is a natural progression and something that users are expecting, but how does one implement this given the complete fragmentation of the user experience given the tremendous number of clients that have sprung up around the great open API that Twitter has supported from Day 1? This presents a very different set of problems than a more closed network.  I suppose though that in the larger scheme of things as featuers are added to the service and API that because of the huge numer of developers and clients that good uses will catch on quickly as they have in the past.

Comments?