I'm interested to see where this goes. My biggest worry about tags is avoiding "Subreddit"-like behavior. That is, things like "Hey #programming, check out this function I wrote!" or "So what does #guncontrol think of..." Blocks of users interested in a tag should not be of one mind, nor should they be assumed to be of one mind on any topic.

Ideally, following tags should be a way of saying "I am interested in #_____ and have strong opinions about it", and not just "I love #_____!" For example, if you're following #atheism, you shouldn't be doing it because you want to say "Hey, fuck religions man!" and get a million nods in solemn agreement. Rather, following #atheism should be a signal that you think there's a lot to talk about on the subject, whether you yourself are atheist, interested philosophy surrounding it, or the sociological implications of it. A Christian who is worried about the growth of irreligion among the youth of America would be someone who could be interested in that tag, for example. (Not meaning to harp on atheism, but merely putting it out there by way of example).

Hopefully, the users of Hubski see it the same way and follow anything meaningful to them, whether they love it or hate it! Keeps discussion more interesting that way.