In my opinion we can't fight against spamers with these methodes. What they want is to leave a link so they get backlinks, so why we do allow them to do so.
I need a plugin which does not allow new members and guests to post links in their first postings.
If they are not allowed to post a text with links in it, they can't post anything. There is no need for new members to post a link. Normally a new member asks a question or give an answer but there is no need to post a link in the first posting. Spamer will not reach their goal to post a link.