Google has been migrating all their properties to work over SSL over the past years and they are still working on that migration process. Google would like to see you make your site work over SSL as well. So much so that Matt Cutts said at SMX West that he would personally love to make it part of the ranking algorithm.
Let me be clear, Matt Cutts, Google’s head of search spam, did not say it is or it will be part of the ranking algorithm. But he did say that he personally would like to see it happen in 2014. Matt Cutts is a senior Google search engineer that has opinions that matter, so I wouldn’t be surprised if Google does announce in 2014 that this is a ranking factor – but it is far off and may never happen.
Making your site run over HTTPS or SSL can be easy for small websites but for really large sites, it would require a lot of reconfiguration and testing. Security certificates are not that expensive these days, depending on which security company you go with. The big cost may be involved in migrating larger and older sites into the new URL structure.
Of course, there can also be an SEO concern with migrating all your URLs from http to https. As you know, Google ranks content based on unique URLs, so migrating from one URL to another, even if it is only http to https, can potentially cause a ranking decline in the short term – assuming you do not properly set up your new redirects.
That being said, most of the new sites my company launches has been defaulted to run over HTTPS instead of HTTP. The costs are minimal and clearly there is a trend happening here. Migrating older sites can be some work but new sites, for the most part, likely should strongly consider going HTTPS by default.
Again, Google’s Matt Cutts did not say this was or will be a ranking factor. He said that he would like to see it become a ranking factor but he does not have the final say on this matter. And if it does become a ranking factor, how much of a factor will that be for rankings? That is another question.