This is a slightly embarrassing confession of benighted ignorance (until very recently), and a pointer for anyone who is still in the dark.
Quite some while ago I gave up looking at the sci.logic newsgroup: what was once a resource has become overwhelmed by the usual spam and porno links, interspersed with the occasional crank posting. Sci.math held out, it seemed, a bit longer but there’s now too much crap, or questions from students wanting homework answers, to make it worth bothering with (so people who used to have something useful to contribute stay away, so it gets even less worthwhile). Where, then, do you go to post serious techie questions in the hope of being read by people who might know, or to browse through spam-free, (relatively!) crank-free, discussions in the hope of serendipitous illumination?
Well, for a certain kind of question there is the terrific FOM of course. But, starting about a year ago, and now really flourishing, there is Math Overflow (which I confess I’ve only recently caught up with). It’s level is grad-student-and-upwards, explicitly not for undergrad homework questions, civil, moderated, well-organized. There are already over 400 threads tagged “lo.logic” with some pretty meaty and helpful discussions (with some overlap, there are almost as many threads on set theory, and there are more on category theory).
So Math Overflow is very well worth logicky people checking out if you don’t already know it.