Impact of nofollow links

[RyanOD]

Does anyone know what the impact of a nofollowed link is on the ranking value any given page has to distribute? For example, if I have 2 links on a page, both followed, I know those links each distribute nearly 50% of the total ranking value the current page has to offer. However, if one of those links is nofollowed, does that automatically mean the other link gets the ranking value cast off by the nofollowed link? In other words, the single followed link now distributes nearly 100% of the ranking value the page has to offer?

It seems to me I remember hearing this was not the case and that the ranking value a nofollowed link would have if it were followed just evaporates. This would mean the single followed link still only passes on around 50%...not 100%.

Is the effect different if the links are internal vs. external?

If any citations are available to justify knowledge here, that would be great. I know a lot of people have opinions about this subject, but I'm not sure anyone knows Google's position.

Thanks!

[RyanOD]

Marcus, Great! That confirms everything I was thinking. We certainly aren't wasting our time page rank sculpting. Rather, I just wanted a confirmation (and appropriate citation) before requesting some changes. Thanks! Ryan

[Marcus_Miller]

Hey Ryan,

If you nofollow a link the pagerank is still split evenly amongst the links on the page and the page rank that would have flowed through this one link is lost.

Google's position is pretty clear on this and is has been clarified by Matt Cutts and in the Google Webmaster Guidelines which provide some examples of the correct usage of the nofollow tag.

Back in the day, you could control the flow of page rank throughout your site like this but that ship sailed a long, long time ago (and crashed against the rocks).

The nofollow tag should be used for a few legitimate reasons.

1. Untrusted links like those from blog comments
2. To prevent a crawler following a link where it can not gain access like a forum profile or login page
3. And to prevent the selling of page rank via paid links

There are likely some other legitimate uses but this covers off the basics.

If you are looking to use this to in a way sculpt the page rank and create more powerful links on pages within your site, don't bother, it won't work and is not the recommended way to interlink documents within your own site. If you want specific pages to not be indexed then use the noindex, follow tag on them or block them in robots.txt.

A few references:

http://www.mattcutts.com/blog/pagerank-sculpting/

http://support.google.com/webmasters/bin/answer.py?hl=en&answer=96569

http://searchengineland.com/friends-dont-let-friends-use-nofollow-77922

Hope it helps!
Marcus