Has there been any testing done that might suggest Google includes the number of ad links with internal links.. or doesn't?
However, there has been no evidence in those nearly four years that Adsense links would count in tha algorithm in any way. It's Google's own ad service so they know what it is. The ads are different with every page load, and they clearly do not help the sites who are linked to. If they don't help the advertiser's site to rank, they certainly aren't going to matter for the more esoteric purpose of ranking the page that hosts them
there has been no evidence in those nearly four years that Adsense links would count in tha algorithm in any way.
I was thinking in more simple terms and not necessarily in the algo, bear with me.
- Page has 12 internal links and no ads, each link gets 1/12 of the pagerank to pass along (assuming all are related, etc,etc)
- Page has 12 internal links and 4 ads in one unit, each INTERNAL link only gets 1/16 of the pagerank to pass along due to the four extra ads. The ad link values don't pass to the advertisers, they are simply dropped a la nofollow.
edit: I'm asking this in part because the number of links in an adsense unit fluctuates and I was wondering how much link churn impacts a page, but that's for another thread. If adsense links DO play a role and DO cause some rank to drop then there might be an optimal ratio to target, a guide as to how many ads a page can support depending on how many other links are on the page etc.
Adsense ads cannot be crawled via a robots.txt directive: [pagead2.googlesyndication.com...] Googlebot is not going to parse adsense ads for links because it cannot crawl them.
Adsense ads cannot be crawled via a robots.txt directive:
They don't need to be crawled, or even parsed, to know the links are there and if they are there, like any other link, do they get a cut of the available rank assigned to them which, in turn, reduces how much the other links have to push?
Its possible. Google certainly throws pagerank away when they encounter a nofollow or a link to something that can't be crawled because of robots.txt.
In the end, it shouldn't matter. Based on my observations, Google has changed their algorithm to differentiate between internal and external pagerank. Within your site, they use internal links to calculate an internal rank for your pages. So if you throw PR away somehow, these internal ranks will be lower. But then it appears that they calculate a separate domain rank for your site and scale your internal rank to your domain rank. So if you throw away a lot of PR, it only changes which pages on your site are ranked highly, not by how high they are ranked.
If they were somehow counting ads as external links and decreasing your domain rank because of it, that could hurt you.