While unsettling, that still doesn't explain the data flow out of Google. Google wants your customized list of email targeting, sure. But they don't want to leak anything proprietary to others to use, such as search history.
Yeah, but if you've got that on your computer, you have much more to worry about then your search history being used for marketing, and they've got much more lucrative ways of making money from you. It's a "It rather involved being on the other side of this airtight hatchway"[1] type situation.
Oh I don't disagree with you at all. I was just thinking of a case where google maps search leads to email spam related to your google maps search and that's all I could think of.