Crawl prioritization: Search engine robots can’t sign in or register as a member on your forum, so there’s no reason to invite Googlebot to follow "register here" or "sign in" links.
Source: Google Webmaster – About rel="nofollow"
So what is crawl prioritization? According to Google suggestion, a page should keep its amount of links under 100. The reason is pretty simple, avoid spam. Most of the websites put their Login and Register links on top of the page where search engine’s spiders crawl it within the first few lines of the source code. This is a waste of resources for search engine as well as the visitors.
To keep this post short, just to remember this few points:
- Less links means your visitors will have a better chance to click on the right and valuable links.
- Lots of links will only confuse your visitors. Are you trying to make them accidentally click on ads?
- Let spiders focus and index on important links by skipping the pages with no content and repeated links. For example, login, Home and Register page.
- Less links means faster indexing and less broken links.
- Too many links will confuse the search engine and thus not giving you sitelink on SERP.
If you’re a DotNetNuke users and wish to put rel="nofollow" on your login or register link, the simplest way to do is download login.ascx and user.ascx from /httpdocs/admin/Skins
All you need is to add nofollow tag as following example:
That’s all! Happy SEOing.