members restricted posting against spam

Petr Koval
2006-07-31T15:26:09Z

is it possible to close write/posting for members (entried users/emails)
to make number of spam messages litle smaller?
and read open for everybody

I know, it is not absolutelly stop of spam
but very litle filter

or what do you all thing about that?

regards
Petr "DjHawk" Koval