What`s in it for the people that help you?
My point is this ... when you`re making a pitch to get people to help you for free, why not follow the same rules of copywriting
that you would for a marketing piece and explain it in terms of the benefits for the people helping you? So far, you`ve explained to us all the ways in which this benefits you ... free content, traffic building, and links back to your site. You might find more people if you discussed the benefits for them.