When looking at the major survey sites out there, it's easy to find many similarities. For example, they all compensate you for your time, most of the time even if you don't qualify for a particular survey. Many of them reward you for getting your friends to sign up, and some of them even give you a little something just for becoming a member yourself. However, just because they have similar features doesn't mean they handle them all the same way. As a result, I've put together some pages detailing the sites that do the best job in a certain area.
Let's be honest, the reason why most people take surveys is to make some extra money in their spare time. All survey sites give you something for completing a survey, and many pay you for each one. It's not always just about the surveys, however, and no site demonstrates this better than Greenfield Online. While the majority of the surveys listed only offer sweepstakes entries, it's many of those same surveys that end up qualifying you for focus groups. Every focus group you participate in is like 5-10 actual surveys, and Greenfield Online has more than it's share.