Very light invisible method to block auto-spam when spam comment is posted. Pings and trackbacks cheks for real backlink.
Anti-Captcha is a transparent spam solution that does not require any end-user interaction.
Upon activation, SpamLord eliminates the potential for automated spam comments, as well as trackback spam.
Comment Spam Prevention without CAPTCHA. No CAPTCHA, No SPAM!
The fight against spam in comments by free service Yandex .NET Web
Defeat automated spambots (even the new 'learning' bots with dynamically named hidden fields) by adding a client side generated checkbox.
A lightweight Formidable Pro anti-spam add-on that requires no interaction with the user.
The AVH First Defense Against Spam plugin gives you the ability to block spammers before any content is served.
Adds new fields and requires new users to register additional fields (such as first name and last name) or any new field you wish to add. Note: WordP
Provides Visually Appealing Captchas to Enhance and Secure your WordPress pages. Fortified with ANTI-SPAM FILTER Protection and SPAM COUNTER.
Blue Captcha is a powerful and highly customized WordPress plugin that effectively protects your WP blogs from spammers and unwanted persons.
This antispam plugin provides very simple(one-click) and powerful captcha for your blog.
Antispam for bbPress 2.x
Our captcha is the free unique anti-spam solution. This captcha does not require any text typing. Moreover, the captcha contains social features.
This plugin utilizes Google reCAPTCHA to help your blog stay clear of spams. You can use this plugin with Akismet and Contact Form 7.
Dead simple and super lightweight anti-spambot WordPress plugin. No captcha, tricky questions or any other user interaction required at all.
A simple and efficient anti-spam plugin
An easy to use wordpress Captcha plugin to prevent spam on your site. You can use Image Captcha to protect comments and the admin panel.
A customisable human detection plugin, that isn't annoying. Seriously.
Todd Lahman's comment spam blocking plugin that blocks automated spam with zero false positives.
This plugin will make your blog more secure by adding rules which spambots will not pass.
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.
WangGuard - MailPoet Connector is a plugin for connect WangGuard plugin with MailPoet.
Extremely simple, 0 configuration and 0 user/admin-interaction anti-spam plugin.
Secure & Monetize your site with Solve Media's CAPTCHA replacement.
minotaur - Rid the internet of text CAPTCHAs!
This plugin protects your registered user base by preventing registration with a disposable email addresse (like the ones provided by mailinator).
This plugin adds a new form of captcha to your Buddy Press registration and comment forms. Use this plugin to prevent bots from spamming your website