I don't like the idea of lots of mini-Twitters... but I also don't dislike the idea of micro communities that have their own personality and/or center of gravity. Also love the minimalistic design.

I think it's best to grade every new platform on its own merits. A lot are going to be rehashes of Twitter, with the same issues and, eventually, the same experience. Posts currently feels different and I'm finding real value in the feed, which is what keeps bringing me back.