From tptacek:

"It was written by multiple authors. Ryan Sleevi is at Google."

I would assume the method it was written in is of little consequence to many, just that Google Docs offer far better convenience when working in teams.

This is a working draft of a findings document that's being actively edited. Google Docs allows for realtime cooperative collaboration, with nice features like chat and annotation of documents. There are a few other collaborative editing systems out there, but they tend to have more hitches than google docs'