Bad Behavior spam-blocking for EE2
Elivan Zoeren created a spam blocking extension for EE2 that uses the Bad Behavior script to weed out spam submissions. In a clarification in the comments to his post, Elivan notes:
Bad Behavior works before Expression Engine starts generating the page, so spammers won’t be able to see your website at all. So it keeps them from spamming SafeCracker, FreeForm, EE contact forms, etc.
The Bad Behavior EE2 extension is free and available now: Bad Behavior for EE2