I like it. Most of my friends have not been willing to move over from facebook, so, like twitter, I end up following people who are interesting that I wouldn’t have known otherwise.
It has /tremendous/ potential that is still somewhat unrealised. Organisations that need social networking features with privacy protections (like, say, student unions for clubs) could install pods which would open their members up to the larger network also. I think it will end up growing along those lines. However, it’s still missing calendar events and groups. When those are introduced, I really think it will gradually take over, growing through affinity pods.