So yeah, some of you probably noticed there was an influx of spambots a little while ago. It seems to be the season for it. We've tweaked the signup process to filter out most of them without making it hard for legitimate users to register.
New users will have to have their first post approved - this helps stop the spam from actually appearing - and I try to check the forums at least once a day. Any other admin/moderator should be able to approve posts as well. Once your first post is approved, you should be able to post freely from then on.
PSA: You people are awful at actually identifying spambots. I just had to wipe about a dozen that made it through approval.
Check profiles. If they've filled out occupation/interest/etc. in all lowercase, probably a spambot. Also check the signature for hidden links, especially if they've recoloured the text.