I hypothesize that you will still be able to see keywords in your Google Analytics reports. Google's Analytics javascript call is already https compatible, so it will work on an e-commerce site running https. Why would Google block their own products from seeing keywords coming from their own engine?
When Google says the website you go to won't be able to see your search keywords or what not...I think that has to do with 3rd party analytics softwares and engines. So the big question is how will this affect seomoz. Since seomoz is pulling data from Google Analytics, if you link it up, I doubt it'll have much of an impact, but then again I don't work for seomoz.
I'm glad that they're introducing https connections as defaults on all their products for the better security, but you know there are other motivations that have to do with control.