Robert Jordan Posted over 3 years ago Luis von Ahn: Massive-scale online collaboration I think you are missing the point Rahi. Online marketers and the tracking of cookies is an entirely different issue. In the case of DuoLingo, you are being provided with the opportunity to learn another language. The world is driven by profit. You might as well get used to it. There is nothing wrong with a person or a group of people reaping the fruits of their labor if it in turn helps someone else.