Could Comments Hurt Your Search Engine Rankings?
I am a strong believer in the idea that comments increase the value of articles. This holds true on small blogs as well as large news sites. Comments expand the conversation, and can provide insight into the original subject matter that was lacking from the piece to begin with.
It is my opinion that the more discussion there is around any given topic, the more informed the reader is likely to be once they finish reading. That said, there are certainly plenty of useless comments out there as well. I'm referring specifically to spammy ones, and they can do more than just damage the reader's experience, but in some cases, they may even affect search engine rankings.
Google Search Quality Analyst Fili Wiese recently tweeted about (hat tip to Barry Schwartz) an article from Richard Baxter at SEOgadget, which details how some spam comments appear to have affected the ranking of a specific page of his in Google's search results.

The moral of the story here is that while encouraging comments on your articles/blog posts is a good thing, it is also in your best interest to keep spam at a minimum. Sometimes this is easier said than done, but if you know that your rankings might be affected, you will have a little more motivation. edit: Online_Marketing/auto___could_comments_hurt_your_search_engine_rankings_.wikieditish...