Adding the nofollow tag to certain hyperlinks is good for SEO. Paid links, affiliate links, links within blogrolls and comments, links crediting images, etc., are all good examples of outbound external links that should be nofollowed.
Why using nofollow on certain links is a good idea?
Basically, using nofollow and dofollow tags…
Read the full article on how to use the Nofollow tag properly.
- Nofollow Your Links? How Long Until Google Notices (seroundtable.com)
- About Do follow & Nofollow Link (seofor24.wordpress.com)
- Wikipedia And The Nofollow Controversy (leccoworkshop.com)
- Choosing doFollow or noFollow (girl-who-reads.com)