Should I set nofollow or dofollow attribute for internal links of my website?
I wonder how important it is to set the correct attribute for internal links. Is it better to set a nofollow attribute or to put a dofollow attribute for the internal links I post on my website? Also what if I just don't give any attribute for my internal and external links. How does Google treat this?
Don't waste your time and energy
You will be wasting your time by using nofollow attributes in internal links as they are not used in PageRank. However, in cases where you don’t want Googlebot to get to your login page, you can use the nofollow tag. There is no harm in your login page being visited by Googlebot. This means that you should avoid using the nofollow tag because it does more harm than good.
Keep nofollow off from the internal linnks
Google sets a number of points without any differentiation to any page which is then distributed equally to pages it is linked to. So, if you use nofollow attributes on any link on a page, then you may lose some points. In the video Matt Cutts prohibits to apply nofollow on internal links. If you add nofollow to any of you page, google doesn't let Google follow the links and all these points get vanished. In Matt Cutts own voice -
I would not use nofollow on internal linksThe reason is pagerank comes into your site, it flows through out your site based on the links that you have on your site. If you add nofollow on your internal links, that’s causing your links to drop out of the link graph. They don’t flow PageRank anymore. So instead of the pagerank flowing around naturally on your site, suddenly some of it just sort of evaporates or disappears. So at least for the links within your own site, I would almost always make sure that they flow PageRank that is don’t put nofollow on those links.
It may appear that some pages needn't be indexed. You may want Google, not to index pages like login page. Search engine spiders will not even attempt to login and/or register on your site. That is why Matt Cutts also suggested not to use nofollow attributes on pages like this.
Now there can be very, very specific situations where you might not want specific pages crawled. For example, the login page, maybe you don’t want if you’re TripAdvisor or Orbitz, or Expedia or something like that, you might not want Googlebot to come to your login page. Because there is nothing for googlebot to login on. But even then, most of the time, it doesn’t hurt to have the login page and search results. It doesn’t hurt to have your privacy page or your About Us page or whatever. So the vast, vast, vast majority of the time I would say, “Don’t add nofollow on internal links”.
In short, Matt Cutts has prohibited the use of rel=nofollow for linking internal pages. This video dates back to 2010. In another video from 2013, Matt answered a similar question concentrated on login page. The video is below-
In this video, he also emphasized on not using nofollow on internal links. But it doesn't really matter if you use nofollow on pages login page. in his voice-
It doesn’t hurt if you want to put a nofollow pointing to a login page or to a page that you think is really useless.
Matt also advised concentrating on the links to other sites and the links created when a new user registers because this is the point spammers may try to infiltrate. And noindex is better than nofollow.