I love how out of one submission of an NPR article to HN there came about 4 different apps that all do an amazing job of making the 'tax receipt' concept a reality
Most of these different apps simply linearly scale the results, which is incorrect. Some taxes are non-linear (such as Social Security, which is only collected on the first $106,800 of income).
What would be useful is if somebody created a mathematical model of the tax system. This model could drive these other sites, and it could also be used in all sorts of "what-if" scenarios.
I don't think this exists, and it seems like such an obviously good thing to have. I guess the problem is that there's not really a mathematical model of the tax system. Everything is subject to some interpretation, and the rules and system has become so complex that it is probably impossible to model.
