From what I've checked (without actually registering), this doesn't seem like a scam to me. It's just that it doesn't seem worth it because you can only make up to $0.80 a day... make that $8.80 a day
if you can get 10 friends to sign up
and do 40 unique searches a day.
On the other hand, if you just sign up and set it as your default search page, you wouldn't have to do any active work and you'd get at least a few bucks a month. Let's say you want money to buy RS membership. $5 is 250 searches. With 31 days in a month, that's... 9 searches a day. Get a few friends to sign up, and it would become very easy. You wouldn't make a ton of money, sure, but it's something.
This is just like Gratis Network (the freeipods.com people). It's not a scam, but it takes time to see any real results, and the company makes a profit from adverts.
Speaking of Gratis... and speaking of trying to get a PSP...
http://www.freepsps.com/ just finish an offer and get 5 friends to sign up.
Those who will remember, will speak fondly of the warm morning breeze.