Stop a lot of spambots from polluting your site by making visitors identify a custom word displayed as an image before commenting.
The most advanced protection against sploggers and spam users registration, is fully WordPress,WordPress MU ,BuddyPress and bbPress 2.0 compatible
Spam Master is the Ultimate Spam Protection plugin that blocks new user registrations and post comments with Real Time anti-spam lists.
Help combat spam registrations by forcing the user to answer a simple math sum while registering for your BuddyPress-powered site
Cognito Forms is a free online form builder that integrates seemlessly with WordPress. Create contact forms, registrations forms, surveys, and more!
Adds CAPTCHA anti-spam methods to WordPress on the forms for comments, registration, lost password, login, or all. For WP, WPMU, and BuddyPress.
Todd Lahman's comment spam blocking plugin that blocks automated spam with zero false positives.
This plugin allows you to implement super security captcha form into web forms.
This plugin will make your blog more secure by adding rules which spambots will not pass.
Spam BLIP stops comment spam before it is posted, using DNS blacklists, existing comments marked as spam, and user defined lists.
The AVH First Defense Against Spam plugin gives you the ability to block spammers before any content is served.
BotSmasher stops spam by checking comments and registrations against the BotSmasher API.
The Advanced WordPress Security plugin Developed by World Web Arts to protect your wordpress website from virus and malicious attack by permission set
WP True Typed is an anti-spam plugin to protect your site from comment spam.
REPLACEMENT of the original Simple Trackback Validation Plugin from Miachel. Performs a simple but very effective test on all incoming trackbacks in o
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