When brands want to find out what consumers think about their product and services, they turn to market research companies. Market research companies are the ones actually administering the surveys on behalf of the corporations looking for data/feedback. Think of online surveys as a type of focus group, except in this case, everything is done online.
Not a “scam” in the sense of the word, but really not a way to earn any type of money. If you can find the companies that do the surveys and do them on your own with out sites like this you will make a substantially bigger amount of money. The “scam” is they take 90% (if not more, to be honest probably 99%) of the survey payout for themselves. Its the same for the “offers”, they will take the majority of the offer from the company, and give you a small percentage, And if that was not enough, they also take a percentage of your payout. This should be illegal as it is criminal to do this to people.