A lot of people do not understand why market research, and particularly online surveys, pay out good money for the simple transaction of giving your opinion when it is asked for. It does seem like a very strange situation for those of us who spend a bit of time on the Internet anyway. But that is the key point. As an Internet user, you represent part of the market that big companies are aiming for. People who use the Internet are likely to be young enough and financially well off enough to have a bit of disposable income. The companies will hope that you spend that disposable income on their products.
However, even if the paid survey makes nothing clear as to who is behind it, it does not do a company any harm to see what an unbiased individual answers when they have nothing steering them to give the “right” answer. This allows a picture to build of what the target market wants in a particular niche, and allows the company to calibrate their product and their delivery to be just what a customer wants.
For this reason you will often find that the surveys start with a control question asking for your age, sex and often your profession. This is important for companies trying to target their advertising. They will pay for all of this information, and by taking part in the survey you can benefit from some of this money. It takes a while to build up good money, but quickly you will learn which surveys are the best to take.