Comment spamming is a common tactic for spammers in artificial link building, a good and moderated blog should always be free from comment spamming, this is to maintain the quality of your blog and easy for readers to go through the comments. We will list down several ways that you should be using to control comment spamming in your wordpress blog.
Implement Captcha Plugin
There are a bunch of lazy comment spammers that use comment posting programs to automatically harvest blogs that allow comment posting and post their post. You can install a CAPTCHA plugin for wordpress as a first level defense. Every comment posting will have to manually type in a series of randomly generated characters or numbers shown in a graphic bar, the comment posting will be disallowed if there is no match between the two. This approach has been widely used in many websites and can help eliminate most of spam posting from auto posting programs effectively.
This option is already available in your default wordpress install, it is a feature developed by the Wordpress theme to help reduce spam comment, it uses a common database of spam posting as a filter. If it is activated, all comments to your blog will be going through this filter for common spam words, spammy comments will not be allowed into the blog. It is consider one of the best tool for popular blogs that receive lots of comments daily.
Manually check comments before showing to public
You should not be lazy, manually check all comment posting before allowing them to appear in your blog, this can help you eliminate most of the spam comments as well as allowing you to understand better what your visitors are feeling about your post. You should note that every good blogger will not ignore comments and they do response to visitors comment promptly. This is an effective way of building a community and increase readership of your blog.