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Long ago, the same question was asked at the forum I give you the link: https://moz.com/community/q/alternatives-to-seo-book-s-rank-checker There are a lot of answers that can help you

I think it really depends on how it's done. You certainly don't just want a whole page of comments with no blog post above them to be indexed on Google, as the experience of landing on that page from search engine results would be poor. You have 50 legitimately useful comments on the post? I find that about 75% of our comments are either outright spam, or poorly veiled attempts at it. You may be able to delete any that are constructive to the conversation. If you paginate the comments to keep some of them off the post in order to speed it up, I'd recommend setting the Robots meta tag on the comment pagination pages to Noindex,Follow.