From Caleb Booker:

Many people don’t have a clue what I’m talking about when I say “I had a meeting with a few people last night” when they know full well I was just sitting alone in my office. Here are some examples of three recent meets:

In each of these examples we’re typing to each other in chat, or speaking in a voice conference call that’s automatically put together by the Second Life client. It’s actually quite a bit easier to do this in Second Life as opposed to some kind of conference-call tool, and having our avatars sitting together (no matter how unreal the setting) gives us a sense of propinquity that makes it easier for us to have meaningful exchanges.

It’s probably worth mentioning that this is all free as well.