Can small, local web mapping services still compete against Google, Microsoft and Yahoo!’s offerings? Absolutely. All they have to do is blow us away with cool new features:
Norway’s Yellow Pages, a part of the Scandinavian search engine and portal Eniro, has just come out with aerial datasets for 1937, 1952, 1971, 1984 and 2004, which you can put side by side and then browse in sync. Try it. (Select “Dra/Panorer” to drag the maps.)
It’s technically well thought out as well — the unique URL for each view contains the date of the desired dataset for each pane — so can send people views of your house (assuming your house is in Norway) together with a view of the area in decades past.
The possibility of having multiple historical datasets available for comparison has been mooted before: One case in India has already demonstrated how useful such a feature can be, especially if the time intervals are small and frequent. This pioneering Norwegian implementation really drives home the potential.