I have a blog based website with some static html pages linked. I recently made all blog links (tags, category, post) nofollow just to target more on the static html pages hosted on the same domain. After a Google cache my rankings went down (-10).
Is there any relation between internal nofollow links and website rankings?
Can we put nofollow to non important links? does it harm the entire website?
I personally think there can be a problem - depending on how it's done, PageRank "circulation" through the site can get broken by internal nofollows. It's something like a blocked artery in a human body that stops the blood from going through from one important part to another.
PR sculpting using nofollow does not work. i would argue it never has - others that it used to, but doesn't any more.
i have removed nofollow from all the sites i work on (external and internal both), except for links where i do not want to pass value (like paid links/advertising), but you could just as well set up a 302 redirect for those.
i also, as a general rule, nofollow any links i am forced to place. i will gladly link to almost anywhere with relevant or good content... i love linking.
but whenever i have to link (as in someone tells me what to do and it is no longer my choice), i nofollow - just to make a point.