The Airbnb one is definitely on the unethical side of the line. I'd be lying if I said I wouldn't do the same thing to grow my business though. I don't think an

The Airbnb one is definitely on the unethical side of the line. I'd be lying if I said I wouldn't do the same thing to grow my business though. I don't think anyone really got hurt by it. The others are mostly fine. Especially Quora. I don't know how anyone could have a problem with the founders... using the site properly themselves?