Interesting you bring this up... I was working on one for awhile that hard a sort of social karma system built in. I wanted to try and reenforce people creating tasks in a game environment rather than just through self-motivation. You were awarded points for completing tasks and able to view accumulated points of friends. I hoped this would allow just a bit more accountability since all your friends can see that you just sat on your ass all day. Same sort of idea of the scale that tweets your weight. There really was no good way I had come up with to make a fair scoring system and to defer cheating. Had I finished it, what it definitely wouldn't have been is anything like this app which makes me feels very detached. I honestly think todos should be fun, otherwise most people won't stick with them.

For the record, this was just one of the smallest projects I could think of to learn a new technology. I think the space sucks but that's largely because everybody does exactly the same thing. It's kind of funny that I couldn't bring myself to work on something that stale even if it was just for me to see.