Review: Top 9 Wordpress Anti-Spam Plugins

By Angsuman Chakraborty, Gaea News Network
Saturday, November 22, 2008

While writing an article about the best security plugins of Wordpress, I felt the need to touch another very important security issue for the bloggers, and i.e. Anti Spam Plugins. If you are a blogger, you must be knowing thousands of spams that actually flood your website everyday. Its irritating, time consuming and above all pathetic to sit everyday and sort out the important and legitimate comments from thousands of spams. Because we can not let go of your opinion for hundred bots. So, here are 9 top anti-spam plugins for Wordpress which will relieve you from those worries and let you read the real comments in peace.

Anti-spam Plugins

(numbers in no preferential order)

1. Akismet

Akismet is a spam filtering service which protects your blog from comment spam submitted through comment form, trackback spam or pingback spam.

When a new comment, trackback, or pingback comes to your blog it is submitted to the Akismet web service which runs hundreds of tests on the comment and returns true or false.  You do not need to maintain any blacklist in your part.

It saves the spams in the database for 15 days in case you want to check it out manually and then automatically deletes them.

The missing part is that you do not have control over your comments. You get a blackbox with no direct control over its actions. You have to rely on Akismet’s decision. However you can submit a comment as genuine comment which is marked as spam by Akismet to the Akismet service so that it learns from your submission.

Many bloggers have complained of commenters being wrongfully flagged as spammers and vice verse.

What if the Akismet web service is down? All your comments will simply go into the moderation queue.

2. Comment Guard Pro

Spams are of different kinds. Most of the users often complaint that even after using a popular spam protection plugin, the purpose is not being served. The reason for that is, your plugin might not have that code snippet to deny one particular category of spammers. Suppose you have WP spam free plugin, so you can never get rid of human submitted spams from that. That is where you will need an almost all-in-one spam protection plugin for yourself.

Comment Guard Pro (for WordPress) is designed to unobtrusively protect your blog against all types of comment spams - trackback spam, pingback spam, robotic spam using comment form, human submitted spam (where the spammers actually goes to your site to spam you; they are the hardest to detect), referrer spam etc. It provides multiple layers of protection against all kind of comment spams.

Comment guard pro  plugins eliminates false positives (marks legitimate comments as spam) and  false positive (marks genuine comments as spam).

It is hard to eliminate false positives for large spam queue size say 2000-10000 manually. It might be ok for 5-10 comments in spam queue.

A big achievement with this plugin is, you have full control over your comments.

It comes with fully documented open pluglet API and examples to enable you to write your own pluglets.

Comment Guard Pro also includes Akismet as one of its spam filtering service.
So if you are concerned about comment spamming in your blog, then this is perhaps the most comprehensive anti-spam plugin for your Wordpress.

3. Simple Spam Filter Plugin

Simple Spam Filter looks for a particular pattern to distinguish a spam from a real commenter, like most of the other Spam filters. The best part for this plugin is, it can work along with Akismet and will display a captcha if Akismet flags a comment as spam. So the problem with Akismet (that it flags legitimate comments as spams sometimes) can be countered with it.

If a comment gets rejected, then an error screen will be shown with an explanation of why the comment was rejected. An optional captcha can also be configured to display, which allows people to confirm that their comment is indeed legitimate.

4. Bad Behavior

Bad Behavior, though mainly used as a comment spam protection plugin has reliable security features too.

It prevents link spams and blocks the robots which delivers it. By acting as a gatekeeper, it prevents spammers from delivering their junk, and in many cases, from even reading your site in the first place. This helps your site’s load down, makes your site logs cleaner, and also contributes to prevent denial of service conditions caused by spammers.

Instead of merely looking at the content of potential spam, Bad Behavior analyzes the delivery method as well as the software the spammer is using.

It is designed to work alongside existing spam prevention services to increase their effectiveness and efficiency.

This is one of the most often upgraded WordPress plugin. You can use it.

5. WP-SpamFree

As I have already said, Akismet was a good fighter but never a reliable one against these spams. God knows how many times I have seen Akismet predicting wrong spammers where I had deleted legitimate comments. Here is Wp-SpamFree that claims to eliminate bots but not humans.

Features (according to the makers)

  1. Virtually eliminates automated comment spam from bots. It ensures that your commenters are in fact, human.
  2. A counter on your dashboard to keep track of all the spam it’s blocking. The numbers will show how effective this plugin is.
  3. No CAPTCHA’s, challenge questions or other inconvenience to site visitors - it just works.
  4. No false positives, which leads to fewer frustrated readers, and less work for you.
  5. You won’t have to waste valuable time sifting through your Akismet queue anymore, because there won’t be much there.
  6. Now with Trackback and Pingback spam protection. and etc

6. Math Comment Spam Protection Plugin

Math Comment Spam Protection plugin for Wordpress 1.5.2, 2.0.x and 2.1 asks the visitor (who is making a comment) to answer a simple math question. This is intended to prove that the visitor is a human being and not a spam robot.

This plugin does not require JavaScript or cookies. It uses a special encryption function; the result of the question is being passed via a hidden field. The result is being compared with the value entered by the visitor – after encrypring this value as well.

7. Spam Karma 2.3

Spam Karma 2 (SK2) is an anti-spam plugin for the WordPress blogging platform. It is meant to stop all forms of automated Blog spam effortlessly, while remaining as unobtrusive as possible to regular commenters

There is a Trackback referrer check and also a captcha backup . There are plenty of tabs with lots of options for general as well as advanced settings in Spam Karma 2.3.

8. Secure Form Mailer Plugin

This plugin creates custom contact form for your blog and secures it from spamming. It has a wide range of features.

  • Support for multiple instances
  • An easy to use dynamic form generation system (any number of fields, in any order)
  • Multiple recipients
  • Multiple file attachments
  • Optional auto reply feature
  • An image verification system
  • Numerous security features (including protection against email header injection)
  • A message template system and etc.


yaCAPTCHA or yet another CAPTCHA is a CAPTCHA plugin for WordPress that adds an image in the comment form of your WordPress application. In order to post comments, users will have to write down the characters that are part of the image. This can help prevent spam from automated bots and that too in a very cool and easy way as most of the other sites use this technology.

In Conclusion

With the increasing artificial intelligence of the bots and spamming codes, it is proving to be harder every day to maintain the accuracy of a comment spam protection plug in. But they are at it. A blog is never a good blog unless it has comments from the readers. So why don’t I ask you to comment now and give me your feedback. Take care.

March 4, 2010: 10:27 am

yaCaptcha is the only one I found working for me. I tried some other captcha programs before, but this one works best and is most reliable of those I tried.

Good plugin, even if it’s free.

Many thanks for posting.

I messed up with going to manually modify comments.php, what resulted wasn’t too pretty, but I got through that.

June 4, 2009: 9:53 am

Thanks for review.
Finally, i like to use yaCAPTCHA plugin. It’s powerfull.

January 27, 2009: 11:54 pm

thanks for the plug-in. You can never have too much protection against those pesky spammers … but hey, I wanted to say what a lovely theme design you have here on your blog. Thumbs up!

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