I've read all the feedback, and agree with much of it. But I think I see something here that a lot of people don't see. At my school one of our simple routines is to go around the class a couple mornings each week, and have everyone say their name, a number from 1-10 representing how they're feeling that day, and maybe respond to some prompt. It's a silly, cheesy, touchy-feely routine on the surface, but when done right it does a lot of good. If someone is low, it's good for others to know that. We give that person some space, and make sure someone checks in with them, without suffocating them. If someone is having a good day, we use that person's energy to push projects forward and help other people out.
Sure, people could do this using facebook or twitter. But they'd have to use those general tools for this specific purpose. There could be some strength in simplicity here.
That said, this will not be an overnight success. If you want to make this into something meaningful, you've got a bunch of iterating to do. You've got a lot to learn about what the specific strengths of this concept is, and cut anything that doesn't build on those strengths. You've got to make it work with fb and twitter, because it probably won't stand on its own.
Good luck, it's an interesting concept.