He said theyre good for extra income, when youve earned the amount then bank it and he said a few popular sites, theyre on the gmtv website. Some people can earn up to £100 a month if u register with a few sites and be persistent with it!
I think you'd need to have a LOT of time on your hands to earn that much. Only one I use pays cash, and I got about £20 last time I got paid but that took ages! Perhaps if you 'cheat' and try to answer all the surveys they send you might earn a lot (i.e. work out what demographic they're after and answer the questions accordingly) but that would be really boring (some of them can be tedious and repetitive enough anyway, even if you are vaguely interested in the subject!!)
Most sites you earn points and exchange for vouchers (Amazon, Boots, Top Shop etc) or other items.
Ones I use are Global Test Market, Valued Opinions and Lightspeed Panel. I did use Toluna as well but unregistered as had a few problems.
I dont know about £100 a month, but I do online surveys but it takes up a lot of time, and you need to have alot of motivation. I get really unmotivated by the boringness of it sometimes.
I use lightspeed which I use to swap vouchers - you can get a £5 Boots voucher for just under 800 points, and each survey pays out around 80 points, but they are long, normally take about 20 minutes, so you can see you really have to work hard.
I also use OnePoll, which pay out small amounts of Cash per survey, the surveys are shorter and they take a couple of minutes max, but they pay 5p or 10p for them. You have to get upto £40 before you can cash out the money though. I have been at it since October and I have nearly reached that.