The comment systems and how to integrate them into your site, is an important, yet often over-looked piece of the on-site SEO puzzle. The comments on your site are VERY important. A lot of comments tell visitors that your site is busy. If it’s busy, then it’s likely to be trusted by more people. If it’s trusted, it will do better in Google too.
However, all of this is dependent on having good quality comments. Comments need to add to the 'conversation' that has gone before them. Put more specifically, do the comments add to the original article, either by way of an opinion, additional information, or a question? Another good type of comment is when a visitor replies to someone else's remarks, but again, only if those replies are adding to the conversation. These are the types of comments you need to try and get on your site. When a website is new, it’s all too easy to approve poor comments just to make the site look visited. Don’t do it! Never approve a comment unless it actually adds something to the post topic and conversation already on-going, that's if there are other comments of course.
Typical comments you should NOT approve include the congratulatory comments, like “Well done!”, or “Great post”. Even “Thanks for writing about this topic in a way I can understand”. Although the latter might sound sincere, it adds absolutely nothing to the conversation because there is no reference to the topic in question.
Get used to approving only the best comments. Even if you don’t get very many to begin with (which is quite possible), great comments add value to the overall visitor experience of your website. Or to put it another way, a website full of poor & spammy comments will put your visitors off and they won’t have much confidence in you or the credibility of your site.