After learning about the Google SSL Algorithm that was launched yesterday morning, I was eager to test my own sites and see if migrating had an impact both in the short-term and long-term in a positive or negative way in Google's rankings.
I jumped at it with my corporate site and have seen no positive or negative signs yet. But I waited to do this site because it is syndicated by Google News and I thought changing the URL will have an impact on inclusion within Google News, thus removing me from the Google News index.
So I asked two different sources at Google about this, one through PR channels and our friend John Mueller, and both said there should be no difference in migrating a Google News syndicated site versus a normal site.
John Mueller wrote on Google+:
I checked with the News folks -- HTTPS is fine for Google News, no need to even tell them about it. If you do end up noticing anything, that would (most likely) be a bug and something worth letting the Google News team know about. A bunch of sites are on HTTPS in Google News, it would be great to have more.
So in the next several days, I will migrate this site over and be the guinea pig for all the rest of you and let you know how it goes. The process thus far for us has been:
(1) Set up the SSL certificate
(2) Restrict HTTPS to my office IP so we can test
(3) Fix any mismatch content errors, mostly due to (a) images (b) embeds (c) social share icons and the like
(4) Test again
(5) Test again
(6) Test again
(7) Set up the proper 301 redirects
(8) Test again
(9) Update the sitemap files and XML feeds
(10) Test again
(11) Flip off the IP restriction and open it up to the world and GoogleBot
(12) Test again
(13) Try and fail to do site move in Google Webmaster Tools
(14) Track Google Analytics and Webmaster Tools data
That has been my process thus far and I will let you know how it goes for both a normal web site and a Google News syndicated web site.
Forum discussion at Google+.