(disclaimer: I worked on Win 7 and Win 8. Don't work at MS now.)
The Windows 7 engineering blog led by Sinofsky was really well received. I worked on a few posts and internally there was an extremely high bar for clarity, accuracy, and usefulness of the content. And there was serious attention paid to feedback.
This post doesn't really say anything other than that the engineering blogs are starting up again - that's what people seem to be excited for.
