In an effort to curb the automatic submission of forms from "web bots" on your site, the folks over at Dotgeek.org have posted a CAPTCHA script that can easily integrate with your current site.

From a note on PHP Magazine: The captcha.php module prevents WWW bots from submitting HTML forms by presenting an image that must be identified before the submission will be accepted. It is very easy to use and integrate because of its simple API and sensible defaults. Built-in timeouts make database tracking unnecessary, and by using data: URIs it does not need any temporary files. For visually impaired users or text-only browsers, a letter riddle can be provided instead of an image. The initial release, Captcha PHP 0.8, adds the double-redirection workaround for the outdated Microsoft Internet Explorer.

Not only can this dramatically cut down on the number of fake submissions/comments that you get a day, but it is also a great way to validate login creation for your members-only areas of the site. I like the fact, too, that for text-only (or otherwise "visually impaired") browsers, a text-riddle can be provided instead of the image. Not quite as secure, but still a pretty good deterrent...