The only problem with rewarding consumers for taking online surveys is that it gives them the incentive to cheat. The more surveys you fill out, the more points you get. So people get creative: They randomly answer survey questions as quickly as possible, establish multiple e-mail addresses to answer the same survey five or six times, or lie about their demographic (a white male says he's a black female, for example) to participate in surveys for which they otherwise wouldn't qualify [source: Frost & Sullivan].
This is where it can all go downhill quickly. In the pressure to make as many pennies out of a nickel, a lot of research corporations will not just sell your answers but the data associated with it. Details that you provide when taking paid surveys such as your name, address, age range can all be attached together quickly to fulfill a lot of larger companies' requests for information (RFI).