r/Fitness does a weekly "Moronic Monday", a judgment-free thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. I thought this seemed like a useful thing to have here - after all, the concepts discussed on LessWrong are probably at least a little harder to grasp than those of weightlifting. Plus, I have a few stupid questions of my own, so it doesn't seem unreasonable that other people might as well.
Any kind of tragedy of the commons type scenario would qualify.
It's not obvious to me how tragedy of the commons/prisoner's dilemma is isomorphic to Newcomb's problem, but I definitely believe you that it could be. If TDT does in fact present a coherent solution to these types of problems, then I can easily see how it would be useful. I might try to read the pdf again sometime. Thanks.