This idea is quite genuine, but I don't know about the company you linked. I used to do it, but it's worthless waste of time and money, I used ciao.com, they don't always send you surveys to do and when they do they're worth like 50p and £1 lol, but they last like 20 minutes. Pointless in my opinion.
There's dozens, if not hundreds of these type of schemes about, nearly all cost you money to join. Not worth the time and effort, unless you are running the scheme, even then it may not be a worthwhile enterprise.
On a personal note, I recall a neighbour who tried to get people in the area to sign up for a similar type of scheme. The thing that impressed me the most, was his wreck of a car with advertisement displayed in the windows, telling people how easy it was to earn £100 an hour. Needless to say, he scrapped the car, and the advertisement seemed to have ended the same way.