Chang Su
A subset of The Energy Information Administration website by EIA category (cost, consumption, production, US states, Census divisions, and international) by fuel (petroleum, natural gas, coal, nuclear, etc.) with browsable relationships by geography and sector. This example focused on different ways to slice and dice the massive amounts of data in the EIA site. This particular scheme is one of several under investigation for an ongoing research project (Government Statistics), thus only a few data elements are actually accessible (a few web pages at EIA).