Value of no-follow links

[Gavo]

I'm curious to understand roughly how much % of value a no-follow link has in building authority relative to a do-follow link?

I understand that Google seems consistently and growingly focused on value - ie. is the link valuable in growing the business, irregardless of SEO - and perhaps therefore the no-follow / do-follow distinction is becoming a more unnecessary dichotomy.

How does Google look at do-follow vs no-follow links? And how much weight now is really given to one compared to the other?

[Linda-Vassily]

I'll keep an eye on his site. Thanks!

[EGOL]

I think that watching Google patent filings is an extremely important thing for an SEO to do.  Google applies for lots of search-related patents and it is likely that much of what they apply for is never put into practice.  If you want a single source to watch for Google patent information, explained in plain English by an experienced SEO, then Bill Slawski's site is where to watch for it....

http://www.seobythesea.com/about-seo-by-the-sea/

[Linda-Vassily]

Interesting—I guess Google doesn't completely keep things to itself, you just have to know where to look. Thanks for the information.

[EGOL]

There is some indication that Google is able to count and may be starting to count "links that are used".  They have filed patents that say that counting "links that are used" could be included in their algos.   Information on patent filings that feature this can be found here.

[Linda-Vassily]

In theory, a nofollow link should not transfer authority. However, I recently read an article by Christopher Cemper of LinkResearchTools that kind of argues otherwise. (He mainly talks about nofollow links passing negative signals.) I don't think it is possible to assign a number to this—it's one of those things Google likes to keep to itself.

In any case, relevant links from high-quality sites are a good thing, whether they are nofollow or not.