What's surprising to me is that you're getting that much motivational power out of Beeminder even without pledging money to stay on your yellow brick roads. Theoretically, that's where the real motivational power comes from -- setting up a commitment device.

Well, you'll eventually have some suggestive data one way or the other; my guess, though, is that there won't be a strong correlation between precommitment amounts and success.

Rather, I expect you'll mostly see people who 1) keep running off roads or giving up, or 2) who succeed after a small number of failures. People who crank up to a midrange and then stay on their road(s) forever after seem unlikely to me. (This is why I think private branding or flat-fee approaches are your best bet for stable and sustainable funding in the long term.)

I could be wrong, of course. An awful lot depends on what population you end up being a cross-section of.

I figure by solving akrasia

That's not going to happen, trust me. ;-) There is no silver bullet for that (i.e., no universal solution that doesn't require extensive individual customization), and I've worked with plenty of people for whom Beeminder would be a curse rather than a blessing.

Part of the point is that humans are not homo economicus: not all values are fungible, and some values are in conflict within a given individual.