Communities should not be rushed... and I'm assuming (perhaps falsely?) that these will serve to categorize content better?

Back in "another life" I was part of eBay's "user advisory group" for setting and creating new categories... and it was a VERY protracted affair of observation-suggesting-testing-observation-suggesting-testing before anything at all was actually implemented. I mention this because if there's one thing eBay is superior at, it's subdividing "content" into meaningful chunks, at multiple levels of granularity.