Sblam! is a web service that blocks spammy posts in blog comments, forums and guestbooks (blocks bots posting adverts for viagra, porn, credit, casinos, etc.). It detects spam server-side and doesn't bother users with any puzzles to retype.
A script installed on your site relays posts to the central Sblam! server for analysis and gives you the result.
It's up to you how spams are handled. Sblam! has very high accuracy (typically 99.8%) and reports when it's not certain about the result, so you can manually moderate the toughest cases.
Yes. It does work with any PHP-based site which uses standard POST forms, but you have to integrate the filter yourself.
Sblam! is intended only for posts that are going to be displayed publicly on the Internet. Please do not use it for private corespondence. Posts sent to Sblam! server are stored and their aggregated data (such as spammy links and IP blacklist) may be published.
Cookies (except a single one which is private to Sblam!) are not sent. You can keep some form fields secret by unsetting them with