Akismet: A plugin which identifies and blocks comment and trackback spam on blogs with integration to various blogging systems.
BBC News - How spammers are targeting blogs: Spammers are turning their attention to weblogs, angering technology analyst Bill Thompson. He calls it "flyblogging."
Big Fractal Tangle: Designing For Lowlifes: Discusses how better, smarter tools are needed to block or remove comment spam in realtime.
Blog Spam Database: Database of URLs and phrases often used by spammers, along with links to related resources and a discussion forum.
Blogspam.org - Anti-Comment Spam Tactics: Series of steps to stop spam in your blogs.
Comment Spam: Google's Toxic Waste Dump: Offers a few suggestions to Google and weblog publishers to thwart those who think they can make money spamming blogs.
Internetnews.com - Six Apart Trains Guns on 'Comment Spam': The blog tools vendor Six Apart plans to roll out an open online authentication system to fight the growing phenomenon of comment spam.
Jeremy Zawodny's Blog - Guerilla Tactics Against Blog Comment Spammers: Suggestion that bloggers create posts that target the same spammy phrases that blog spammers want Google to find.
Jeremy Zawodny's Blog: Using mod_rewrite against comment spam bots: Very short tutorial.
Kalsey Consulting Group - Comment Spam Manifesto: Weblogger crystallizes the thoughts of many in declaring a cyberwar on those who inappropriately post in guestbooks and weblogs.
Learning Movable Type: Concerning Spam: Types of spam seen on blogs.
MSNBC - Spammers now clogging blogs, IM: Spam has never been limited to e-mail. But now, commercial pitches are increasingly popping up in online chats, instant messages, cell phones with text messaging and weblog comments.
MT-Blacklist/Comment Spam Clearinghouse: A centralized blacklist database of blog spam URLs.
No Guestbook Spam Anymore: Offers instructions for webmasters for avoiding and eliminating spam in guestbook.
OJR : Bloggers Declare War on Comment Spam, but Can They Win?: "Here's a look at the battle so far."
Simon Willison's Weblog - Solving Comment Spam: Feasible ways to stop or thwart comment spam.
Simon Willison: Blacklisting Comment Spam: One man's efforts to create and maintain a blacklist.
Six Log: Comment Spam: Spammers are abusing comment systems to increase their rank on Google. Here are some steps to take to reduce or eliminate this problem.
Spam Huntress - Spam cleaning for blogs: Spam huntress dissects blogspam.
Typepad Vs. Commentspam: The steps that Typepad has taken in order to rid its users of spam comments.
Webmaster Kit: Stop Spam: Offers a script using the Turing Test, intended for spam prevention in guestbooks, blogs and wikis.
Wild Mind: Essays about comment spam and how one blogger is fighting it.
Wired - Googlemania: The (Evil) Genius of Comment Spammers: Background of the phenomenon of comment spam and how bloggers responded.
Wired: When the Spam Hits the Blogs: Owners of weblogs have recently noticed that their referral logs have become the newest target for spam.
Yoz Grahame's Cheerleader: Seven quick tips for a spam-free blog: A list of tips aimed at webloggers to reduce the problem of comment spam.