Spam comments has always been a problem in the blogosphere. Akismet and Spam Karma 2 are two of the most common spam protection plugins for wordpress blogs. What these plugins do, however, is simply catch spam comments and put them in queue for the administrator’s moderation.
Spam in blogs (also called simply blog spam or comment spam) is a form of spamdexing. It is done by automatically posting random comments, promoting commercial services, to blogs, wikis, guestbooks, or other publicly-accessible online discussion boards. Any web application that accepts and displays hyperlinks submitted by visitors may be a target.
Adding links that point to the spammer’s web site artificially increases the site’s search engine ranking. An increased ranking often results in the spammer’s commercial site being listed ahead of other sites for certain searches, increasing the number of potential visitors and paying customers.
Spam comments are usually done through a program and/or machines. They are normally automatic once they’ve bookmarked your site. Now, although Akismet and Spam Karma 2 catch those spams and prevent them from being posted directly to your comments, they do not prevent them from reaching your comments (worse, they don’t cook them for breakfast! hehe). They help keep spam from being published, but not from reaching your comments.
As a result, you’ll need to check your admin panel regularly and browse through the captured spam comments for any erroneous catch. This is surely irritating, especially if you’re encountering an average of 10 to 20 spams per day (much worse is the case for other more popular sites).