I think it's better to have actual data than to just state your opinion or mention "that's what google said"
I agree. Everything I noted is grounded in my personal experience and observation. When I am guessing or expressing an opinion I note it as such, particularly when it's speculative.
As far as going by what Google says, it depends on who is saying it and the context of what was said. Certainly they don't tell everything and details are left out. And some spokespeople do not work directly with the engineers (and have degrees totally unrelated to search) and in my opinion are less trustworthy sources of information.
Speculation and theories can be a waste of time if done poorly Speculation can be a waste of time, especially when there are no citations to any scientific research or patent that would demonstrate that a particular phenomenon is within the realm of possibilities. The idea that social signals might be a ranking factor is a case in point. It was proposed based on observations that many top ranked sites have active social profiles or likes. It was proposed that maybe social signals were affecting the SERPs.
But the downside of that theory is that there was no research or patents at all surrounding social signals for the purpose of improving the search results. It was non-existent. No search engine or scientist had proposed using social signals as a ranking factor. Couple that with the denials from Google that social signals were not a ranking factor then it's pretty clear that the entire theory was nonsense and many businesses could have saved themselves the trouble had they considered whether or not it was within the realm of possibilities.
Social signals could be used as a way to verify authority, but that's not a ranking factor. :P
Social signals versus social activity It's important to make a distinction between signals and activities. Social signals as a ranking factor is discredited. It's malarkey. ;) Social
activity however can be beneficial for driving traffic, building awareness and indirectly can help build links (among other things).