It’ll be nearly two years since Google, Yahoo!, MSN and a host of blog CMS providers got together to launch the nofollow initiative to combat comment spam.
From a link building point of view, I’ve always wondered how nofollow treated mass link building efforts like the ones we bloggers experience firsthand everyday. If the big 3 search engines say the nofollow tag is a step in the right direction, why is comment spamming and all its whitehat/grayhat variants still considered a valid link building tactic by some.
History of Nofollow
Here is SEW’s summary of how Google treats the nofollow tag:
If Google sees nofollow as part of a link, it will:
- NOT follow through to that page.
- NOT count the link in calculating PageRank link popularity scores.
- NOT count the anchor text in determining what terms the page being linked to is relevant for.
MSN behaves the same way:
Any link with this tag will indicate to a crawler it is not necessarily approved by this page and shouldn’t be followed nor contribute weight for ranking.
Yahoo! on the other hand has been “misbehaving”. As Remi van Beekum posted at the High Rankings forum last year, Yahoo! has taken a different route: it’s following and factoring nofollowed links in its ranking algorithm:
I recall Tim Mayer saying they will follow the nofollow links because most links that are not ‘trusted’ are actually valid links, at the SES in NY February/March. They just weight less than links without the nofollow tag.
With the two year anniversary of the nofollow initiative coming up in a few months, I decided to test that theory again via GlobeVisibility.com (nofollow) which I bought recently (and which Noel discovered today hehe). I bought the domain last 10/23/2006 and hosted the test page 6 days after. Nofollowed links were provided by Macalua.com (see footer). I wanted to keep the experiment running longer but the domain has been outed and I can’t keep people from linking to it anymore.
Here are the results of my experiment:
On Indexing
Google doesn’t follow through to the destination URL. Googlebot doesn’t visit and the URL isn’t indexed.
MSN doesn’t follow through to the destination URL. MSNBot doesn’t visit and the URL isn’t indexed.
Yahoo! follows through to the destination URL. Yahoo! Slurp visited and indexed the URL.
On Seeing Backlinks
Google and MSN don’t return nofollowed links when doing a link: or linkdomain: search. Yahoo! does.
On Ranking
As they don’t see other domains with the unique test keyword, Google and MSN only return pages on this blog.
Yahoo! seems to give weight to the anchor text of nofollowed links. Globevisibility.com, the target URL of the nofollowed link on Macalua.com is #1 in Yahoo!, beating this WebRank4 blog for the test keyword.
Hasty Conclusions
- Google and MSN follow nofollow, so comment spamming and all its white/gray variants don’t give any ranking/indexing boost to a site.
- Yahoo! doesn’t follow nofollow, so comment spamming and all its white/gray variants still give a ranking/indexing boost to a site.