> A few years ago, after someone somewhere claimed, like you, that Usenet is still healthy, I had a look back at the group to see what it was like: still dominated by those same crackpots.

Usenet's not really a single entity. I used it fairly heavily from about 1997-2005; most of the groups I read then are now either tumbleweed or overrun by spam. But a couple of them are still running along happily (if a little smaller than they were). So I think 'still healthy' is pretty contextually dependent.