Chris's Random Ramblings
Interaction between people in virtual worlds is a richer experience than using IM or IRC. Its much more than just a communication channel as you can actually do things with other people. For example, Kelly seems to spend just a bit of time shopping with other people in SL ;-) But there are other things such as playing Avatar Chess, where a separate person plays each piece on the board. I'm not sure how well chess strategy through democracy works. But I can certainly understand why virtual worlds such as SL are attractive to people who are geographically separated, and want to be able to do more than just be able to "catch up" with what the other has been doing.
Linden Labs recently changed their terms of service. One of the good modifications has been to explicitly allow people to use 3rd party clients if they wish. I don't know of any other fully functional ones out there yet, but it does clarify the situation a lot more for the open source libsecondlife project. There are quite a few changes I'd like to make to the client, so hopefully a fully-functional open source client is not too far away.