Want more half-baked ideas? See my ideas tag
How about the population of Boston in the years 1625-2013? Or the wages of bartenders in that fine city over the years? Or the peak summer temperature each year? Not so good.
My half-baked idea is a “wikipedia for curated facts”. These can be derived from many sources, but are presented in a uniform way (by place, time, variable, etc), with references to back them up.
This would be a great way to inject factual content into the air-headed anecdote-based nonsense that passes for opinion on the internet.