"They don't have your best interests in mind" is also relative. Keep in mind the diversity of clients who have or receive money to buy ads, from advocacy groups to attorneys involved in ecological litigation to your local bookstore to a new credit union in your area to a fast food chain to a complete out and out scammer running worthless seminars.

Part of the deal is that they still get to work from incentives on their end. But this alone doesn't rule out your interests or even your best interests.

The subjective beauty of this is that depending on who you are, even the seminar scammer might be both obvious AND the best news you've heard all week, because you have been waiting for a specific opportunity.

BTW I really recommend watching Harrison Ford in The Mosquito Coast. There's a bit of a diamond of truth buried in the story, kind of an anti-anti-ad message that is really important to consider.