The mapping function, although only at country/US state level (I think) is brilliant too. I now know that - in the last five days - Wyoming is the US state least interested in Victorian London

whereas New Yorkers are (relatively) fascinated by Victorian history:

even if the resulting image looks unfortunately like a missile strike on New York state. Here's to you, Manhattan. (And yes, I know I'm ignoring the differential in their population; let me dream!).
The figures are still quite low - I have about 1500 visitors a day, so it will take a while to get the full pictutre, but I'm already spending too much time on this ... I'm not the first to point this out, but the internet is brilliant.