Google likes to try and shape the web like Microsoft likes to shape the PC world. Often, their more bizarre attempts fail. This will be just another failed attempt, I predict. Sorta. Bear with me. I will explain how this ranking factor is applied and what it all means.
Google touts the notion that the web would be better if all web sites were served with HTTPS and if all sites had certificates. While this is true for sites that require log-in accounts and other services that are better off with encryption, for most sites this is just plain unnecessary and, in fact, a ridiculous notion.
Not to be a conspiracy theorist, in fact, I often hate these theories, but I think there is an alternative reason. And I think the answer is as plain as the nose on our faces. Spamdexing. Or at the very least, control over who is a quality provider and junk websites. And admittedly, in part, Google is right. Certificates can at least be a valid and worthwhile step in the honesty/forthright category. It will be a step that sites can take to up their trust game. I am in favor of that. The question is, how necessary is it? For most sites, not very, if at all.
How Google has weighed HTTPS and certificates for years:
It is a really simple process that has existed for years now. It is not something new, despite Google announcing it recently. Often, Google will cop to something old by pretending it is new.
The earliest notion of PageRank was applied to the site and not on a page-by-page basis, despite the fact that it was calculated page-by-page. Google realized its mistake in confusing the issue and changed the game, and rightfully so. Is PageRank for the site or for the page? Today, the answer is the page, of course. But the confusion over PageRank for any site remains as it still exists within the toolbar and in the questions on this site. So what does Google do? Announce that PageRank for any site will disappear. But is it really disappearing?
No. Because a long time ago, PageRank for the site was renamed, not publicly, but internally, as site rank. It is more conceptual. Why would Google ever admit to a site rank when PageRank offered so much confusion and concern? Keep that in mind. A portion of site rank are factors which fall under the umbrella of trust. Remember that too. It will come in handy.
So here is how it works:
As factors in trust rank, HTTPS (encryption use), a site certificate, and the certificate provider quality are measurable factors. Trust rank is a factor in site rank. Site rank is a factor in the placement in the SERPs. Tah dah! It is that simple. Yes. HTTPS is a factor. It has been for quite some time, but the trickle-down effect is limited. Why? Because a good trust score can be had without HTTPS and certificates. So is it a big concern? No. Not that I can see so far. But if Google decides to, it can become a much larger factor over night by simply changing the weight of the various metrics. Let's hope not.