EDITED and hour later: A couple of people have pointed out it's back, they've made some changes and marked it as public now.
There was another article on this same topic this morning with this:
"Google's engineers have not ignored worries about the security and privacy risks. To their credit, they've gathered them together into a single document and they've clearly been engaged in understanding what people are worried about. It's just that they've concluded the concerns aren't that big a deal or can be dealt with to their satisfaction."
That Single Document is here, and I went and had a read this morning, but now I get permission denied, I guess it was getting too much attention?
https://docs.google.com/document/d/1YHcl1-vE_ZnZ0kL2almeikAj...
I wish I would've save a copy now. It hand some decent details on the various vulnerabilities and how they are handling (or ignoring) them.