I’ve covered SSL several times now in post and video form – and if you’ve decided that there’s a benefit to converting your website to SSL I urge you to do it correctly. That means going through your website to make sure that all of the elements you are utilizing (all of your scripts, images, iframes, etc) are being served from a secure source. Serving them from a non-secure source will cause a content-mismatch error and while this may not break anything really – it’s just bad form, plus Google doesn’t seem keen on supporting it much longer.
During this mornings Webmaster Central Office Hours Hangout on Google+ John Mueller said at the 18:30 mark:
I imagine at some point, we will say you will have to serve really clean HTTPS for us to show that in the search results. I don’t know. I don’t think that there will be any kind of penalty around that. Just that we may say, we won’t count this as HTTPS, so it won’t get that small HTTPS ranking boost.
Going by the choice of words that John Mueller uses I’m not going to chalk this up to a google confirmation just yet. However this is a great warning to start working on perfecting your SSL setup throughout your websites various pages – especially if you want to keep that miniscule SSL boost.