Google’s Ranking Factors 2011 - Question on Social Signals

[blueSummit]

Dear Community,

analyzing the SEOmoz Ranking Factors 2011 Study (http://www.slideshare.net/randfish/smx-munich-keynote-moz-ranking-factors), I have a question regarding slide no. 33.

What exactly does the "#of Linking C-Blocks to Page" in this Graph mean? Are this the different C-Blocks related to the Social Site´s specific Domains / Subdomains?

Thanks for your answers.

[RyanKent]

C blocks refer to the IP used to host a site. URLs are formed as AAA.BBB.CCC.DDD. So if your IP is 100.150.222.001 then your C block is 222. Often all servers with the same host share a C block. Changing from a shared server to VPS or other changes with the same host often does not have any effect on your C block.

So if you create 10 sites with the same host and provide links between the sites, those links are devalued.

[blueSummit]

Hi Ryan, thanks for your answer, but maybe I have to specify my question

I wanted to know, if the number of linking C-Blocks in this Graph is related to the C-Blocks from the single domains and its subdomains, for examle Facebook.com:

the Spanish Subdomain eu-es.facebook.com has got the IP 69.63.189.11

the Dutch Subdomain nl-nl.facebook.com has got the IP 66.220.153.19.

So in this example we have two different C-Blocks for Facebook.com. Is that the meaning in this Graph?

[RyanKent]

My understanding is the C-block bar has nothing to do with social factors, but instead is being used as a control measurement.

Prior to social sites becoming so popular and other algorithm changes, the strongest off-site correlation for Google ranking factors was the number of linking C-blocks to a website. The graph is being used to demonstrate how Facebook shares and other social metrics are so incredibly strong they overshadow the number of linking C blocks metric.

That is how I interpreted the graph. If anyone else read it differently I would welcome the feedback.