I read the study... It was interesting, and it says repeatedly throughout the paper that correlation is not the same as causation... So really more than anything it should be looked at as a guide to best practices and not a how to guide...
The best way to succeed is to look at those that are successful and copy what they are doing... This is simply a study of what those at the top of the search engine rankings are doing, not really why they are at the top of the search engine rankings.
Is Papa Johns at the top of the search listings for the word pizza because they have a google + page... No, they have a Google + page because they are very successful at selling pizza and interacting with their customers... Thus correlation is not causation... But if you're going to build a national pizza chain would it be in your best interest to build a Google + page... ahhh yaaa...
Read it for what it is. Not for what people want it to be... Even in the paper they say they are not Google and can't tell you what the algorithm is that Google is using. But they can tell you the major areas where it, or more precisely the folks at the top of the search rankings have changed in relation to what they were doing last year...
Its a guide to current best practices not a guide on how to rank tomorrow...
Enjoy.. DFM