I argue to people that I'd rather have my photos on Googles servers than on the friendly local Dropbox clone.

Why? Because I know Google has systems in place to detect sysadmins browsing in data unrelated to their job and I know they have fired people over it even if was tought to have been done with good intentions.

Edit: as for tracking I wish they would up their game and stop providing ads for <insert eastern country here>-dating.<tld-of-the-day>

I wish they would take into consideration that I am happily married with more than 3kids, belongs to a subset of the population that has way less than 10% divorce rate and I might even be in the market for a new car at some point.

In fact I would even tell them if they asked.

There's surely a Wildean quote in there somewhere.. "The only thing worse than your data being sent to people you don't know..."

That's a puzzle question worthy of a board of ethics interview.

Depends -- WILL I know them afterwards?

The people you do know will purchase the information from the people you don't.

#2 I believe. Better the NSA than your auntie.