There are lots of legitimate companies that make profit using third parties like this. Mostly third parties hoping to find people to complete surveys, watch ads and possibly answer a question about the ad, and other types of advertiser's targeting techniques. Basically, people need exposure to sell their product, and the bigger companies are willing to pay you to help them achieve that. Peanut Labs is a big name among these third parties, and it CAN be a pain for the users sometimes when you are constantly rejected from surveys even after going through a large portion of it and then not receiving any payment since you didn't finish; besides the surveys though there are many ways to earn, including many companies that will pay you for actual work, such as finding hotel phone numbers and addresses for online references, helping to filter nudity on social media sites(which is uber fun btw), and lots of other boring, repetitive stuff that pays out in the form of whatever currency, in this case it would be platinum, while you, the developer, would get your pay from the third parties that promote the offers.

some big companny's use them too
like facebook, zynga, some online games like tribal wars
and they do it
so i tink if you have the right site/company it works fine
maybe you'll find a good one in another game :)

trust me those arent legit youll end up doing 5 surveys and it will get all ur info and say "sorry we cant help you" or some shit like that *learned it from a friend

-Trololo-