Have you considered having some type of joint member ship with gasbuddy? They provide the information of lowest gas prices in your area. Since (at least most of us) are already inputting in the gas prices into Fuelly, and GasBuddy gives out points when you update the information which can be used for prizes, perhaps theres some way of joining the two together to have the best of both worlds, without having to visit two different sites?
I like that idea personally, but I'm not sure GasBuddy would go for that. We don't know anyone over there, and they don't have much incentive to join forces with us. So yeah, nice idea, but a lot of business-type folks would need to meet and shake hands for this to happen.