SpamSpan filter

The SpamSpan module obfuscates email addresses to help prevent spambots from collecting them. It implements the technique at the SpamSpan website (a German version is also available). The problem with most email address obfuscators is that they rely upon JavaScript being enabled on the client side. This makes the technique inaccessible to people with screen readers. SpamSpan however will produce clickable links if JavaScript is enabled, and will show the email address as example [at] example [dot] com if the browser does not support JavaScript or if JavaScript is disabled.

This technique is unlikely to be absolutely foolproof. It is possible in theory for a determined spambot to harvest addresses from your site no matter how you disguise them. But research suggests that the by far the great majority of spambots do not bother to attempt to collect addresses which have been hidden using JavaScript. Indeed, most spambots cannot currently read JavaScript at all.

Here are a links to the results of a few experiments into the efficacy of JavaScript obfuscation. Let me know if you know of any more.

http://www.cdt.org/speech/spam/030319spamreport.shtml (2003)

http://nikitathespider.com/articles/IngenReklamTack.html (2006)

http://nadeausoftware.com/articles/2007/05/stop_spammer_email_harvesters... (2007)

Releases

Official releases	Date	Size	Links	Status
6.x-1.3	2009-May-04	16.68 KB	Download · Release notes	Recommended for 6.x
5.x-1.4	2008-Sep-06	12.39 KB	Download · Release notes	Recommended for 5.x

Development snapshots	Date	Size	Links	Status
6.x-1.x-dev	2009-May-09	17.58 KB	Download · Release notes	Development snapshot
5.x-1.x-dev	2007-Nov-17	12.39 KB	Download · Release notes	Development snapshot