Ann Smarty poses an interesting question on Search Engine Journal. As blogs are communities, it's useful to comment and leave your thoughts. But what if you add your link to the comment? Is it spam?
There are numerous tools that can check to see whether the comment is spammy and it depends on your blog installation (MovableType versus WordPress versus any other platform). But Annie notices that search engines are smart enough to factor in whether the comments are spam and also check for relevancy, comment content length, similar content on other blogs, blacklist terms, and other elements to determine whether it's spam or not. She concludes that if you add relevancy and ensure that you don't violate these rules, you're not spamming at all and you're adding value instead.
In the Sphinn forum discussion, bloggers acknowledge that it's important to put all comments through moderation (if you care about your blog). Apparently, some people actually do rank well after spamming blogs with their comments. If your blog is your baby, don't let those comments through.
Forum discussion continues at Sphinn.