Comment spam handler systems include

• Akismet (Python API 1), (Python API 2), (WSGI lib), (other projects)

• Wordpress-only systems such as Defensio, SpamKarma2 and Bad Behavior

Note: Akismet has received plenty of complaints, some from SEOs, and so not always easy to take seriously, but some seem worryingly legit.

It would be nice to support contribution to anti-spam projects such as

• Project Honey pot

As always, we steal interesting ideas from Sam Ruby. For example:

• "Automatic Preview"

• "Captcha this!"

• "Spam update"

• "You might be a spammer if..."

• "Beware of Strangers"

Example from http://intertwingly.net/blog/2004/01/17/Spam-Update, which came from pressing "Preview" on comment form of http://www.intertwingly.net/blog/1692.html . Comment preview HTML from Intertwingly: IntertwinglyCommentPreview.html.txt

Wikipedia has a useful survey of the issue

* http://en.wikipedia.org/wiki/Comment_spam

Sixapart has an excellent analysis of spam-fighting techniques, oriented towards MovableType, but nevertheless almost a must-read:

• http://www.sixapart.com/pronet/comment_spam

The Trac project has documented their own battle against spam:

• http://trac.edgewall.org/wiki/SpamFilter

See also

• "Real Web 2.0: Battling Web spam, Part 1"

• "Real Web 2.0: Battling Web spam, Part 2"

• "Using data to fight webspam" - Google

• "What Google Knows About Spam"

• "Six Apart Guide to Comment Spam"

• "Unobtrusive OpenID"

• Sam Ruby's advice to Tim Bray on writing a comments system

• "OpenID for non-SuperUsers"

• "SVG Comments"

• "Stopping spambots with hashes and honeypots"--Ned Batchelder -- excellent discussion

• Defensio - Akismet competitor with less neg rep

• Apache BlogSpamAssassin notes

• Trac SpamFilter

  • Trac ticket on Spam prevention

• wsgiakismet -- probably never to be used: Akismet has a bad rep

• chongqed.org AntiSpam Recommendations

• THE Wiki anti-spam discussion

• MoinMoin anti-spam features

• SpamLookup - "yes, it's another anti-spam plugin. I would have called it MT-DSBL 2.0, but the feature set grew beyond the name, so a more generic name was chosen. This is a 2.0 release however... the plugin deserves more seniority than a 1.0 release, since it was built of the carcass that was MT-DSBL 1.1."

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