I believe it's against the rules, though I haven't actually looked at the rules in a long time.  What I do know is that if you send out advertising via PMs, members are going to report them and you'll get banned.  So whether it's allowed here or not, just don't do it.  Not only that, but people fucking hate getting spam PMs around here.  I know I certainly do, and it doesn't take much for me to report a PM if I think it's even the least bit spammy.

Oh, whoops!  I have the very bad habit of only reading the first few posts in a thread before posting, and you'd think after stuff like this I would learn.  Thanks for quoting the rule--and that's what I figured.  I did recall reading that unsolicited PMs was against the rules.  That actually doesn't make sense, since members generally don't solicit PMs themselves and 99.99% of the ones I've received I wasn't expecting.  Anyway.