Routers and therefore your ISP and intermediaries will no longer be able to "sniff" the content of the "packets" between your browser and Google. This change blocks all sorts of intermediary collection of statistics and keywords about your activities. If you've tried a "trace route" (tracert), you can see all the rest stops your packets take on their merry way.
It wasn't long ago ISP's talked about inserting their own ads onto any webpages served to users through their services. Using https/ssl blocks this (mostly).
Perhaps some competitive analysis services will lose their data sources.
As far as I have read, the NSA already has agreements, and therefore hooks, into encrypted communications. So this change may actually benefit the NSA and degrade the news media's abilities to collect information.
I looked through my logs and the first request from Google for https pages was about 2/23/2012, and the request rate from Google has now built up to what seems as high as the non-https requests to sites. Literally millions of sites now probably have duplicate content due to Google's indexing https pages.
My webhost(s) and the conglomerate that owns these hosts seems to serve all websites on http and https by default. Of course this is a different issue.
Just some speculation.