Doing a relocation from Manchester in UK to Geneva, Wolfram Alpha says the equivalent salary should be lower in Geneva. That's because they substitute London data for Manchester and then calculate based on that. They only seem to have good coverage for US cities. The rest come from a UN cost of living report from 2014.
That could definitely be possible. Teleport, however, is missing capitals of US states
I've seen a few sites that do this kind of thing, but rarely with such elegance. Good job!
Good looking! Potentially very useful . . . And an acquisition target for LinkedIn?