I'm less likely to donate to an online project than to buy the book outright - I'm something of a luddite for online shopping.

I do convert from web novels to buying physical books with some frequency; I started reading Jo Walton, Aaron Allston, and John Scalzi that way. So you might consider it as a way to get readers off the fence about buying your backlist, too.

Now that my wife has a Kindle, I'd consider paying for a kindle download of something like the Shadow Unit project, too.