What is comment spam? This post provides a nice explanation. Essentially, someone or, more likely, someone’s web crawling robot posts a comment to a blog or forum. The comment may be gibber jabber or it may be some hollow compliment, but it has nothing to do with the article or discussion. The point is simply to post a link, or multiple links, to a particular website. Check out Wikipedia’s Spam in blogs article or this Wired article for more on the phenomenon.
Recently, my little blog here has been the target of a lot of comment spam. Initially, I let some of it through. I would reply to the comments as if they were serious and I would change their links to point to Zombo.com. This was a pointless exercise which I conducted merely because it amused me. I am no longer amused.
I love reader comments. As an author, it’s always nice when my work has made some kind of impression significant enough to prompt someone to take a few seconds and provide feedback, even if it’s negative. So if you’ve got something to say, by all means, use the comment form. And when you do, go ahead and fill in the field for your website, even if it doesn’t relate to the discussion or post at hand.
Check out this excellent post/podcast on the subject.