This site was receiving hundreds of spam comments a day. They were not being approved, but it can become very annoying when trying to get to the genunine comments.
There are a few plugins out there which will help stop/reduce spam. I used SI Captcha For WordPress, which basically adds a spam captcha to comments. You can decide whether you want to set the capture code to easy or difficult.
The plugin worked well and from hundreds of spam comments a day, I now receive a couple.
If you are interested in the plugin it’s available for download at the WordPress Plugins site. Click here
You may also have thousands of pending spam comments, and deleting them all can be time consuming. Another plugin I use is delete pending comments, which allows you to delete all pending comments at once. The plugin is available for download from the WordPress Plugins site – click here
If you recommend any spam reducing plugins, please post a comment to let us know.