This is a great idea, and I've been thinking of something similar. Some people, including me, work better when there's someone waiting for the work with some deadline. This works out badly if you're working on your own thing, but people like this can be very productive under a good "boss".

So my idea was a web app where people could sign up to be "bosses", and you'd have some karma system to figure out who the good bosses are, matching them up to the "employees" who sign up to get bossed around to do the tasks they've set for themselves. Now, you'd have to put in measures to make sure bosses don't get abusive (make it part of the karma system I guess), ways to match up people with their boss, etc. But it seems like a neat idea that might just work. I just don't know if you could find enough people who like being a good boss (or at least like getting the karma points associated with good bossing), as well as enough people who'd sign up to be bossed around.