1. Up there someone said that they had to DL something. If DL is required, then people won't join. Its just that simple. Paranioa is a way of life here in bitcoinland, and most of us will not download anything.
2. I have tired different sites like this in the past. I always have had a problem with conversion. I am convinced that this is intentional. Either offers are pointlessly vague, or outright scams. Once I took a survey, and 90% of the way through I got a message saying "sorry but you do not qualify for this survey." WTF! They should have determined this at the beginning of the survey! I think that some of these offers are straight up scams. If you want your site to be successful you need some way to vet the offers and eliminate the ones that are scams or at least unreliable. This would make your customers happy I think. I don't go to these sites anymore, not even as a hobby. The conversion rate is so low that it is basically a waste of time. However I think there is a great demand for this type of service, so if you can make your website GOOD then you stand to be very successful.
Good luck!
but this site is for mobile, so it'll always need download an apps (android/iOS/win8 mobile), but it's convert well.
NOTE: This project is now suspended, i'll check again until all got cleared, since some users using bluestack on pc, that's make the offers not get converted -_-