I suggest that you provide the signature limitation information in the welcome email. I was totally clueless about this and checked everywhere before I advertised my site that I wasn't contravening any rules.
When I signed up I had access to create the signature and when I posted, the signature reflected in the post. An hour later, and the signature has been removed. The advert is now in essence useless and I'm only allowed to post it once according to forum rules.
It's would be a nice feature to include this in the welcome email as some forums do.
I plan on hanging around here as I like what I see, so I'll get to the 31 post requirement, so that's not an issue for me, but just wanted to make the suggestion.