Beeminder (http://www.beeminder.com is a "self-tracking system that uses monetary incentives to help you stick to your goals".
The service looks like an interesting complement to Skritter. I admit that I haven't used it a lot yet but it looks promising.
I see two options:
(1.) Skritter copies and adapts some of the functionality.
(2.) Since both services have APIs, integration would certainly be easy.
In comparison with the better-known service StickK (http://www.stickk.com), founded by several economists out of academia and recommended by Dan Ariely, Beeminder is specifically made for quantifiable goals.
"Beeminder is the only self-tracking system that uses monetary incentives to help you stick to your goals. If you just want self-tracking you have a lot of choices and if you just want commitment devices you have more and more options as well. Beeminder combines self-tracking and commitment contracts: keep all your data points on a Yellow Brick Road to your goal or we take your money. The combination is powerful. We call it flexible self-control."