On Site Comment

3rd party comment system

• fb comments
• disqus
• intense debate
• js-kit
• sezwho

self-hosted comments

• threaded comments
• subscribe to replies
• reply by email

Anti-spam options (for app-handled comments)

• akismet (free for personal use, not for commercial use)
• reCaptcha (free, bought by google)
• app's "own" captcha
• moderate all comments
• moderate comments if they contain N or more links (default: N=1)
• only allow comments from authenticated users
• autoapprove comments from a commenter after first approval
• moderate all comments for content items older than X days
• close commenting for content items older than X days
• ip-based throttling (system will only accept N comments per M units of time from a given IP)
• system-wide throttling (system will only accept N SYSTEM-WIDE TOTAL comments per M units of time)

Security by obscurity?

• require random special inputs
• disallow extraneous inputs
• require that a form take at least N units of time to complete (spammers may submit immediately, people take at least a couple seconds to type something)

Suggestions from "User-generated spam - Webmaster Tools Help"

http://www.google.com/support/webmasters/bin/answer.py?answer#81749

• rel#"nofollow"

Use a blacklist to prevent repetitive spamming attempts.

• Google often sees large numbers of fake profiles on one innocent site all linking to the same domain. Once you find a single spammy profile, make it simple to remove any others.

Add a "report spam" feature to user profiles and friend invitations.

• Your users care about your community and are annoyed by spam too. Let them help you solve the problem.

Monitor your site for spammy pages.

• One of the best tools for this is Google Alerts. Set up a site: query using commercial or adult keywords that you wouldn't expect to see on your site. Google Alerts is also a great tool to help detect hacked pages. The Keywords page in Webmaster Tools lists significant keywords found on your site, so it's a good idea to check this regularly for unexpected and volatile vocabulary.

// (end content from google.com)

Further thoughts and links

• Use non-descriptive form names (i.e., not "comment")
• http://www.projecthoneypot.org/
• http://www.stopforumspam.com/
• tiny orwell? (old)