John Asked a Question : I Run a shopping portal with 40000+ products listed divided under numerous categories, is there any advantage of adding Nofollow attribute to internal pages of my shopping portal?
John first of all you need to check out what all pages are the most important pages and what all pages can be avoided. In case of a shopping portal you would obviously have a lot of pages which are useless in the site example : Order page for each product, description page for each product, contact pages, about pages, reviews/rating pages etc and these pages should be given a Nofollow attribute in order to pass page rank to more important pages like the main categories and main product pages.
NoFollow tags are also used by most bloggers who wanted to avoid spammers who used to comment in order to gain backlinks from the comment sections of blogs. This is because if there would be a No-Nofollow in a blog, and a commentor links to his website, there are very less chances that the commentors website link would be relevant to the blog and this could get both the websites penalised and especially the linking website ie the blog in this case though there are several antispam plugins now.
Now this is the very main reason NoFollow attribute was started and is now used by most webmasters in order to avoid page rank passing also called as PR leakage.
You can also find the usage of Nofollow tags on this blog in the top header section where i have added Nofollow tags recently to my Advertise & Contact page because passing page rank to these pages would be useless. Hope this helps you out in understanding better about Nofollow and you can manually add this attribute by just adding this code in your link codes.
<a rel="nofollow" href="https://www.amitbhawani.com/blog/advertise/">Advertise</a> | <a
rel="nofollow" href="https://www.amitbhawani.com/blog/contact">Contact Me</a>
<a href="YourWebsiteLink" rel="nofollow">LinkTitle</a>