Sadly, opportunistic jerkfaces aren't limited by our privacy-hat-wearing engineer imaginations. They can devise much, much worse schemes we would dismiss in five seconds out of "ethical" concerns. (privacy=dead, remember? do anything to track people and manipulate them into giving you money. if you aren't selling anything, sell the tracking as leadgen.)

I pretty much assume that anything I post to any website could someday come back to haunt me. Expect no privacy on the internet, and you won't be disappointed.