How long will you be able to sustain this? I have a fairly small site that has virtually no traffic, so I would love to use this but what happens if you end up with a large number of sites using this? And assume that the donations don't cover the expenses. Do you have a fallback plan?
I would've liked to use this but it doesn't look like there is a release, so you would have to know how to build it yourself to even be able to try it.
I will set it up this weekend and see how it goes.