[jmke]

For some time now we have installed a custom registration process where the user needs to select a photo of a PC hardware piece. If they click on the correct photo they are allowed to sign-up.

We haven't had any automated bots registering since we implemented this, but this doesn't stop human spambots from posting their crap. Some are after posting their links on popular sites to get higher up in the search ranking;

To discourage these people from even wasting our time and prevent search engines from picking up their links I've added http://en.wikipedia.org/wiki/Nofollow to all outgoing links on the forum;

The longest a spampost has survived on the forum is 65 minutes, our moderators delete the account used before search engines can even scan the added content. But in case we do miss one; we can now be certain that the spammer will get no benefit from having his links posted in our forum!