Free WordPress Anti-Captcha (anti-spam botblocker) pluginFree
Anti-Captcha is a transparent spam solution that does not require any end-user interaction.
The aim of this plugin is to prevent automated attacks (by bots) on the following WordPress actions:
- Posting comments
- Registering for a new account
- Requesting a lost password
When a comment is posted without a valid Anti-Captcha token, it shall be instantly marked as spam. This way, you can always manually approve this comment in hindsight if it appeared to be sincere.
Author: Filidor Wiese
Source from: WordPress.org