In this Whiteboard Friday, Rand looks further into using correlation data properly for SEO.
Google and Bing – not so different on an SEO basis
In June 2010, SEOMoz looked at many variables for SEO, and discovered that the optimisations that worked for one engine also worked for the other.
Facebook shares highly correlated with higher Google rankings
In March 2011, Facebook shares were the number 1 metric that would correlated with ranking higher in Google.
Sites without Nofollow links have negative correlation
March 2011 showed Nofollow links have a high correlation with good ranking, and vice versa. This may be because normal websites have Nofollowed links that are natural. Hence, websites with no Nofollow links look suspicious to the engines.