The forum admins (the moderators don't actually administer the vBulletin software) have turned on the "post moderation" feature. The software examines new posts, and if it believes that the post might be spam, it won't display it until it has been approved by a moderator.
The criteria used by the filter are, like those of all spam filters, mysterious and often inexplicable. For example, it seems to be very sensitive to posts that have certain kinds of links in them. Given that this is a forum about web hosting, that means it will be a little over-sensitive. So, if your post is held for "moderation," don't take it personally!
The moderators will deal with these as quickly as possible. If your post doesn't appear immediately, however, please don't just resubmit it, since it will end up back in the same moderation queue.
This may produce some annoyance, but the mods currently spend an inordinate amount of time "taking out the garbage," so this may help.