I wrote some time ago of a service called Pay With A Tweet. Basically you have something to give away, you want to give it away for free, but would like a Facebook share or a Tweet in return.
It seems, from readers comments on the original post, the Facebook share option on Pay With A Tweet no longer works.
Step up Cloud:Flood, which does exactly the same thing as Pay With a Tweet. I haven’t tested Cloud Flood yet, but if you have share your thoughts below.