Hi, I was like one of the responders here and did surveys a lot.
Most are a total waste of time and definate scams. There was one company that certainly offered you lots of surveys, but I would spend 10-20 minutes or longer answering questions only to be screened out and told I wasn't suitable! I'm sure they were using my information but just not willing to pay for it.
One company asked me to test a product for them and join an online community forum to discuss the product. I was paid £75 and told that I had done an excellent job. After this I wasn't getting any surveys and found that they had dropped me from their list.
I only have three survey companies that I do now and they have sweepstakes, prize draws and/or money to earn. But they are upfront and honest that you will not earn huge amounts of money unless you win a prize.
One woman I spoke to on an on-line forum said that she had done surveys for years and earned not bad money. But she claimed to be with 200+ companies???? I don't know how true this is, but I think writing articles, blogging and answering questions is much more enjoyable and probably earns more than surveys. Hope this helps.