SEOmoz recently asked Matt Cutts some questions.

The most interesting answer from Matt Cutts was this:

Rand Fishkin’s question was, “Does Google recommend the use of nofollow internally as a positive method for controlling the flow of internal link love?”

Matt Cutt’s answer was, “Yes – webmasters can feel free to use nofollow internally to help tell Googlebot which pages they want to receive link juice from other pages”.

Below that it says:

Matt’s precise words were: The nofollow attribute is just a mechanism that gives webmasters the ability to modify PageRank flow at link-level granularity. Plenty of other mechanisms would also work (e.g. a link through a page that is robot.txt’ed out), but nofollow on individual links is simpler for some folks to use. There’s no stigma to using nofollow, even on your own internal links; for Google, nofollow’ed links are dropped out of our link graph; we don’t even use such links for discovery. By the way, the nofollow meta tag does that same thing, but at a page level.

Matt Cutts clarifies in a comment:

More like people can use it for internal links if they’re power-user-y enough to want to sculpt PageRank flow within their site at the link level. But I’d say that most regular webmasters don’t need to worry about link-level PageRank flow within their site. I think saying “power users and webmasters should be employing on their sites” overstates it a little. It’s available if you want to get into that much fine-grained control.

Whenever I see a site that has rel=”nofollow” on the internal links for the purpose of manipulating PageRank distribute, I say to myself, “This site is giving very clear, machine-readable indications that it is attempting to manipulate search engine results”. It reminds me of when people used to put the same exact keyword in the title element, the h1 element, and throughout Web pages in bold and italics. It resulted in obviously over-SEO’d sites and was eventually abandoned. I don’t use rel=”nofollow” on my internal links because I expect that it’s only a matter of time before that technique goes the way of the bolded, italicized keywords.

Rel=”nofollow” is a microformat. You can read more about it on the rel=”nofollow” page on microformats.org. Rel=”nofollow” was submitted by Matt Cutts and Jason Shellen from Google:

This specification is (C) 2005-2007 by the authors. However, the authors intend to submit this specification to a standards body with a liberal copyright/licensing policy such as the GMPG (http://gmpg.org/), IETF (http://ietf.org/), and/or W3C (http://w3.org).

I recommend reading the open issues section which talks about some of the problems with rel=”nofollow”, such as that it “does not mean what it says. [It] does not mean ‘do not follow this link’, rather it means ‘do not add weight from this link’.”

I also recommend reading Google’s announcement about rel=”nofollow” which says, “We’ve also discussed [rel="nofollow"] with colleagues at our fellow search engines and would like to thank MSN Search and Yahoo! for supporting this initiative”.

So Google submitted rel=”nofollow” to a standards body and got Yahoo and MSN on board. Then they decided to extend the meaning.

The PageRank Sculpting Issue

The issue here is that rel=”nofollow” does not mean “do not follow”. It means “do not vouch”. If Google suddenly extends the meaning to include proprietary uses, such as manipulating the flow of internal PageRank, it breaks the standard.

For example, Yahoo and MSN might suddenly realize that by adding a slight penalty to sites that over-optimize by adding rel=”nofollow” to internal links in the template that it helps clean up the SERPs. If different search engines interpret rel=”nofollow” in different ways then the standard is broken.

Why did Google submit rel=”nofollow” to a standards body and then casually extend the purpose?

I think that Matt Cutts’ answer to Rand Fishkin’s question was not thought out completely, and that it is only a matter of time before Google retracts this feature of rel=”nofollow”. Breaking standards so that they don’t work the same across all systems would be evil.

The Solution

• Search engines should ignore rel=”nofollow” on internal links. A Web site always vouches for itself whether the Webmaster adds the internal links or the users add the internal links. The purpose of rel=”nofollow” was to combat spam comments in blogs, not sculpt Google’s proprietary PageRank.
• Change the name of rel=”nofollow” to rel=”novouch” or rel=”noendorse”. See the rel=”nofollow” open issues section for more possibilities. Rel=”nofollow” would be deprecated, but search engines would still read rel=”nofollow” as being identical to the new form called something like rel=”noendorse”. This would clear up confusion about the microformat’s purpose.
• A standard way to control robots already exists: it’s called robots.txt .