The 4 Best WordPress Commenter Blacklist Plugins

We looked for the very best WordPress plugins to stop comment spam, and were pleasantly surprised: the best offerings didn't use intrusive captcha methods at all. Instead, an old favorite remained an able WordPress commenter blacklist plugin and three other plugins added additional and welcome spam-blocking functionality.

http://wordpress.org/extend/plugins/nospamnx/

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If you've ever commented on a blog using a captcha spam-blocking system, you know how annoying that is. Instead of inconveniencing your readers, why not stop comment spam in a more...let's say, STEALTHY manner? One WordPress commenter blacklist plugin that does just this is NoSpamNX.

NoSpamNX uses CSS to add invisible fields to your comment form. If these fields somehow get filled out, that raises a red flag for NoSpamNX and the comments as well as the commenters get blacklisted. Now who would fill out invisible fields anyway? That's right, spambots will. And spambots will get blocked.

_{Image Credit: Screenshot ©NoSpamNX}

Akismet now comes with every WordPress install, but it earns a mention in this list for 2 reasons:

• You still have to activate Akismet with an Akismet API key (easily obtained; simply follow instructions from within WordPress).
• The next plugin in this list works in tandem with Akismet to give Akismet superpowers and a cape.

Akismet uses its own database of known spammers and spam-detecting criteria to decide if commenters deserve to be blacklisted and lets you review the spam it blocks before trashing it. Many people report using Akismet alongside with NoSpamNX. The plugins play well together and perform complementary spam-checking services.

http://wordpress.org/extend/plugins/top-spammers/

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Block Top Spammers prepares a blacklist for your .htaccess file, blocking comment spammers at the source. It reviews comments marked as spam in your database to create this blacklist. The advantage of having a blacklist in your .htaccess file is that it reduces server load by blocking spammers from accessing your site at all.

Block Top Spammers will work hand-in-hand with Akismet and NoSpamNX.

http://wordpress.org/extend/plugins/invisible-defender/

Invisible Defender, like NoSpamNX, blocks comment spam by adding invisible form fields to your comment form. It works on the same principle, too: spambots blindly fill out every field in a form, visible or no, thereby raising a red flag for Invisible Defender.

Because invisible fields are visible to human users who surf via entirely text-based browsers, Invisible Defender adds a special message letting any people seeing these fields know not to fill them out. Bots won't detect these messages.

For comprehensive comment spam blocking that doesn't keep real people from commenting, we recommend activating Akismet and using it in tandem with either NoSpamNX or Invisible Defender. For even more blacklist power, try using Block Top Spammers as well to cut known spammers out of your site entirely. With tools like these, comment spam on your WordPress blog should soon be a thing of the past!