Gosh, that's such a terrible thing to do. I've only received a few requests so I didn't realize it was such a big deal, but I think it's a good idea to stop giving out invites. Or the next time you set invites up, raise the post count to some ridiculous number so that no spammer will ever get past.
I actually signed up here after I got my DoA membership because this forum is so much more relaxed and diverse.
I don't post much because I don't have too many dolls to talk about, but I really do like the forum and I check it every day. But I don't really dislike DoA, the people I've met there were very friendly.