Crawlers aim to find and qualify the content of a page. If a page only presents a small amount of content, it will not be able to be used by search engines. Search engines tend to reward content quality and content freshness. Of course, it is difficult to ask you to rewrite your content or to extend it. However, there are tips such as UGC to reinforce the content of a page.
- Make sure that your comments are in the html source code to be taken into account by search engines
- Make sure that your module for comments does not generate URLs/pages in an endless way - if that is the case, change the way you can respond to comments without generating new URLs to avoid creating links in the source code. You can do that by using technologies such as AJAX or any other technology that does not create an AHREF link or, use the method of link encryption.
- Make sure that you send your users to the right page for review, meaning in the right language (see example below where a Portuguese speaker left a review on the .com website)