Sblam! — antispam filter for forms on the web

Protects forums, blog comments and guestbooks from spam. Does not torment users with text to retype or quizzes to solve. Does not block users who have JavaScript disabled or use uncommon browser.

Features

• Large black list of words and links based on auto-learning bayesian filter.
• Verifies sender and links in Project Honeypot and LinkSleeve databases, taking into account popular networks with dynamic IPs.
• Because all remote tests are done asynchronously (e.g. using custom asynchronous DNS client), testing takes at most a few seconds.
• Supports ISO-8859-2 and UTF-8 and Unicode semantics. Won't be fooled by special or CJK characters.
• Uses custom efficient non-XML API with on-the-fly compression and integrity checking.
• Tweaked for spams typical on Polish pages, but supports English as well and should perform well regardless of language used.
• Reports certainity of the score, allowing to virtually eliminate all mistakes with moderation of edge cases.

FAQ

How does it work?

A script installed on your site relays posts to central Sblam! server for analysis and gives you the results.

What if filter mistakes legitimate comment for spam?

It's up to you how spams are handled. Sblam! has very high accuracy (99.8%) and reports when it's not certain about the result, so you can manually judge toughest cases.

Does it work with WordPress, phpBB or <any other system>?

Yes. It does work with any PHP-based site which uses standard POST forms, but you have to integrate the filter yourself. Wallace has written a simple WordPress plug-in (plug-ins for other CMSes are welcome).

Will future versions of Sblam! be free?

Yes.

Does Sblam! violate privacy?

Posts sent to Sblam! server are stored and read indeed, but please keep in mind that these are posts which you intended to publish on the Internet anwyay.

Cookies (except a single one which is private to Sblam!) are not sent. You can keep some form fields secret by unsetting them with unset($_POST['secretfield']).

Alternatively I recommend Spam Karma 2 or a lesser Big Brother — Akismet.

Questions?

License

1. Privacy is not guaranteed. Posts will be stored and analyzed in order to improve quality of filtering.
2. Client-side Sblam! can be used freely even on commercial websites.
3. Accuracy of filtering is not guaranteed.
4. Availability of the service is not guaranteed.

Links to this site from Sblam!-protected pages are welcome (but not required).