I won't be giving any guns away though.

Oh bummer, I won't bother writing to Pew then.

I think communities are perfect for topics that aren't that popular. First of all because there's someone supervising it. Not like tags or keywords. And if the keyword or tag isn't popular enough, you can't even find them sometimes. So that's the second good thing when the communities are better than just tags. You really can find like-minded people there.