What is "Marketing" at Microsoft?

Heather writes, "So I thought I would start off explaining a little bit about what is considered marketing here at Microsoft. I'm not really sure how we came to know a number of business functions as marketing, but it is what it is (or kind of is what it kind of is). There are gray areas that I probably don't have enough space to debate here (actually, I probably do later...are you interested?)...like technical evangelism. Hybrid roles that require a focus on not only core marketing talent but also deep hands-on technical expertise. That's for later. For now, let me explain what we know of as marketing here at Microsoft." What is "Marketing" at Microsoft?