I was advised a while ago to disallow comments in the robots file, so that articles can be better ranked for their keywords. See below my complete robots file.
You should definitely let Google index your comments - it’s just an additional free content, which very often ends up being a valuable addition to an article. What you should consider doing though is making all the links in comments NOFOLLOW.
I agree with making the links NOFOLLOW this’ll discourage the spamming. I would personally Google to index the comments as they will provide a constant stream of fresh content. Great for traffic as long as people stay on topic
The line Allow: /wp-content/uploads
is invalid and redundant - anything that you don’t disallow is automatically allowed, you neither need to nor should use “allow”.
I don’t see any harm in allowing Google to index your comments (as long as you make the links nofollow, as others have said). It gives you more indexed content, which means it’s more likely that the site will appear in someone’s searches. That’s particularly true for people who may remember commenting on a blog but can’t remember what the blog was, they may do a search for their comment as the only way to find it!
I would encourage Google to index your comments, you rank for a lot of great long tailed keywords when users comments on your posts. It also will keep you website “updated” which Google loves new content. All of these small things could help your post rank better for your main keyword.
Don’t allow google to index your comments.90 percent of the comments are spam or just to create backlinks using the Name/Url feature available in blog comments box.Indexing your comments results in reducing the intensity of your site’s main objective and also help’s other site’s backlink to be indexed.