Akismet filter comments for spam –
details from wordpress.com:
- Automatically checks all comments and filters out the ones that look like spam.
- Each comment has a status history, so you can easily see which comments were caught or cleared by Akismet and which were spammed or unspammed by a moderator.
- URLs are shown in the comment body to reveal hidden or misleading links.
- Moderators can see the number of approved comments for each user.
- A discard feature that outright blocks the worst spam, saving you disk space and speeding up your site.