As webmasters we have a tendency of becoming too caught up in link juice at times, shunning and overlooking nofollow links in favor of dofollow. Well I’m here to remind you that the nofollow link is still very much your friend for these 3 reasons.
Traffic – Duh. Nofollow links can be great sources of traffic, oftentimes more so than dofollow links are. Any links which you get from forum posting or blog commenting are going to be nofollow generally, but these are two very targeted and valuable sources of traffic just the same. Remember that part of the reason that you use dofollow links to begin with is so that your site will eventually rank better and you’ll subsequently get more traffic through the SERPs
Natural – Webmasters who exclusively target dofollow links appear to Google to be unnatural. Therefore, it’s necessary to have a good number of nofollow links to your site to appear more natural to search engines so that it doesn’t look like you’re collecting links with the express purpose of affecting the SERPs (search engines HATE this).
Crawling – Let’s not forget that nofollow links are still important in the sense that search engine spiders still use them to sniff out the content of your site and get a better idea of what your site and that particular page is all about.
Valuable – Secret bonus reason number 4! Finally, don’t believe that just because we’re taught that nofollow links are worth nothing in terms of link juice that it’s true; the idea that nofollow cuts off all link juice altogether is simply not true.
The fact is as I mentioned in point number two, SEOers and webmasters have always exercised a clear preference for dofollow links because of the link juice aspect of them. Given that that’s what Google is preaching as well and the fact that they hate people manipulating their search results, (and this is speculative) Google could have begun placing a greater emphasis on nofollow links as it’s more natural given that no one is trying to exploit nofollow links in the way which they are exploiting dofollow.
The major point to take away from this is that SEO is not an exact science; it will always be evolving so you can never take one’s word as a certainty, even (or especially) from the largest search engine in the world.