Drupal equivalent module for Akismet Wordpress plugin

Akismet

Akismet is a Wordpress plugin that checks your comments against the Akismet web service to see if they look like spam or not and lets you review the spam it catches under your blog's "Comments" admin screen.

Mollom is the Drupal equivalent of Akismet and is a popular spam prevention service module which is used by more than 30,000 Drupal sites. If you already have an Akismet account, then Antispam might be useful.