I tried it for a while and had a lot of good political 'arguments' with an incestuous group of bloggers on Xanga. I ended up dropping it because it took a fair amount of time when I had little, and only a small group of people read the page. The conversations were good, just very topic-specific. I think the only time I opened up and said something personal, the people who spoke up to comment made me wish I hadn't to begin with.
Overall it's a really great thing, and I think it will be a large tool in keeping 'the world' (politics, business, etc) a bit more honest in the future. I have no idea if I'm remembering this correctly, but I think there is some kind of law they are trying to make about reducing what you can blog about regarding politics. Wont ever fly though.