I think I would like to try this. Seeing it done twice has really got me interested in this. I think the key is that you're held accountable for how you spend your time due to the screenshots.

Reminds me of how a guy hired someone to slap him when he got off topic while working:http://hackthesystem.com/blog/why-i-hired-a-girl-on-craigsli...

I don't have a Mac, so I guess I'll have to build the screenshot/webcam stuff myself this weekend.