If you are a blog owner using WordPress to power your blogs, you might be well verse with the problem of comment spam. One way of preventing spam on your blog is to moderate each comment manually. But is it really worth the time and effort? I would say no!

If you would like to remove the menace of blog comment spam from your blog, then you can use some great plugins already available in the WordPress plugin repository. Below is a list of 7 best plugins that can handle the blog comment spam problems for you.

1. Akismet

Undoubtedly the best, and the most used plugin used to curb blog comment spam. Akismet checks your comments against the Akismet web service to see if they look like spam or not and lets you review the spam it catches under your blog’s “Comments” admin screen. You can trust Akismet completely since it comes from the developers of WordPress.

2. AVH First Defense Against Spam

The AVH First Defense Against Spam plugin gives you the ability to block spammers before any content is served by identifying them at the Project Honey Pot, a local blacklist or the local IP cache. Visitors trying to post a comment are checked at stopforumspam.com. Stop Forum Spam is not used to check before content is served due to the amount of requests, which overloads their infrastructure.

3. WP-Hashcash

WP Hashcash works because your visitors must use obfuscated javascript to submit a proof-of-work that indicates they opened your website in a web browser, not a robot. If the javascript check fails, WP-Hashcash can either put the comment into moderation (default), put the comment in the akismet queue, or delete it depending on the settings you chose.

4. bcSpamBlock

bcSpamBlock ensures that the client is a human by using a small bit of javascript on the comments page. Users with Javascript enabled will never notice any difference. For users without Javascript, they will have to copy/paste a short code into a textbox to confirm. The plugin works quite like WP-Hashcash.

5. spam-stopper

This plugin works in stopping spam by allowing you to place a random question along other comment fields that a user must fill up, and fill up correctly. It only shows up when you are logged out, so you don’t have to fill it in if you’re an admin. On top of this, it also adds javascript validation to the form to ensure the required fields are filled in.

6. Bad Behavior

Bad Behavior prevents spammers from ever delivering their junk, and in many cases, from ever reading your site in the first place. This keeps your site’s load down, makes your site logs cleaner, and can help prevent denial of service conditions caused by spammers.

7. Defensio Anti-Spam

Defensio is an advanced spam filtering web service that learns and adapts to your behaviors and those of your users. Apart from spam filtering, it also provides malicious content detection, profanity filtering, URL categorization, script detection etc. In my experience, Defensio Anti-Spam works best when used alone. I’d turn off Akismet if I was to use Defensio Anti-Spam!