The nofollow Tag: To Follow or Not To Follow?

The no-follow tag (rel=”nofollow”) was introduced a while ago in order to stop comment spam on blogs and is now often used by webmasters to stop the leaking of “link juice” to external websites. In recent years, it has been proposed that webmasters can use the no-follow technique to move PageRank around their own sites and prevent the indexing of so-called unimportant pages on their websites. While this sounds straightforward, is this something that can be used safely?

It sounds fairly easy: use the no-follow tag on your own website to prevent the spreading of link juice to pages that are considered un-important or pages that are informational only and do not generate any money. Examples of such pages are the privacy policy and the contact us pages. However applying this no-follow technique has to be done and planned for carefully if you don’t want to run into any potential indexing problems.​

The no-follow tags can be applied to internal links of a brand-new website and the chance for getting it wrong is fairly small. But if you apply the no-follow tags to pages of an established website in order to move PageRank around, you could run into some serious indexing problems: You could lose not only the PageRank of the pages you apply “no-follow” to, but your entire site could lose PageRank all together due to search engine spiders being caught in “loops” created by the incorrect application of the no-follow tags. Of course, you’ll find this out months later, when you have lost precious PageRank and visitors.
In my opinion, it’s better to use the no-follow tag on your blog if you have to use it at all. I don’t recommend using it on your regular (established) web pages that already have PageRank. Even your privacy policy and contact pages are important “contributors” to the overall PageRank of your entire website.
PageRank is a trademark of Google
Source http://www.seo-bliss.com/seo/the-nofollow-tag-to-follow-or-not-to-follow/