WordPress 2.7 introduced a number of new features related to Comments. This included features such as threaded (nested) comments and break comments into pages i.e. comment pagination.
Though these features were well received by the wordpress community, the option break comments into pages introduces a duplicate content issue. If you choose to turn on the break comments into pages setting (under Settings >> Discussion), WordPress 2.7 breaks the post into multiple pages, with comments spread across those pages.However the main post content and the title and description tags, will remain the same for all such pages. This will create duplicate title or duplicate description issues, if you or someone else link to the comments page of the Post, rather that the main post and search engine spiders try to crawl those links.
WordPress 2.7 comment pages of posts have unique URLs. These are automatically generated by the WP 2.7 by appending “/comment-page-n/” to the end of the Post URL, where n stands for number of the comments page.The pages represented by these comments pages are duplicates (except for the comments). If you have a Google webmaster Tools account, you can notice these duplicates getting reported under Duplicate Title Tags or Duplicate Meta Description, in case someone links to the URL of your comments page of post rather than the main post URL.
Platinum SEO Plugin now introduces a new option to add “NoIndex” meta tag to these comments pages of posts.This is turned on by default.With this option, you can now safely enable the option to break comments into pages, without worrying about duplicates. With this meta NoIndex tag, Search engines are prevented from indexing these Comments Pages of Posts.This option has been introduced in version 1.2.3 of Platinum SEO plugin.
Another option introduced in version 1.2.3 of Platinum SEO plugin (PSP) is to add NoFollow tag to Category links in breadcrumbs of Posts or Pages, if the PSP options to nofollow category listings on posts or nofollow category listings on pages are chosen.
Enjoy Version 1.2.3 of platinum SEO Plugin 🙂