[onehost]

via usergroups and promotions.

set usergroup with your post setting requirements.

setup promotions so when they reach your requirements
then the member would then be auto promoted to
that usergroup level.

ie:

newbies on my forum are very limited until they can prove themselves, they
have limited pm, limited this, that, no blog access, no sigs, etc...

once they create 50 posts, then their promotion kicks in, and their
usergroup access will be dumped to the next level, so once they get
50 posts, then will get more mail for their PM, sig allowed, blog
allowed, etc, and so on...this is not very complicated at all...

the number one complaint I get is from spammers wanting to know
why they can not drop links and run the moment they signup....

and if they act up after they get a promotion, then place that member
into a special usergroup with limited access until they can behave....