Martin Splitt from Google said that having unanswered comments on your site or webpages does not negatively hurt your rankings in Google Search and is not a bad SEO thing. He said Google Search does not look to see of your comments get answered or do not get answered.
This question came up at the 14 minute and 19 second mark into the August SEO office hours segment.
Question: What is the SEO impact of leaving user comments unanswered under blog posts?
Answer: None. There's no SEO impact. It's text on your pages, the comments are text on your pages but Google Search doesn't check if that piece of text means that you haven't answered a comment or have answered a comment. Text is either there, then it matters or it isn’t, then it doesn’t.
I have never heard this question asked before and while I do make an effort to reply to comments here, sometimes there are just too many for me to reply to. I reply because I love the SEO community, and even those who troll me. I don't reply for any SEO specific reason.
Here is the video embed:
Forum discussion at YouTube.
