That may be because you were trying to post a link.
Posts from ImmInst users (not Members) with < 10 posts who try to post a link are now send to a moderation queue.
This should go some way to deter spammers.
Sorry for the inconvenience if you are not one of them!
Edited by caliban, 28 June 2010 - 09:17 PM.
s.b