I don’t know how I managed to miss out on Historypin by an organisation called We Are What We Do. Historypin is a website that lets you overlay old photographs and other media on Google Street View imagery.
The Smithsonian Magazine has a short interview with Nick Stanhope, one of the creators of Historypin. He sees Historypin primarily as a means to re-build the ties between generations:
[…] we think that by boosting the interest in local heritage and by making it exciting and relevant to people, by starting conversations—across garden fences, families, different generations and cultural groups—about heritage, we can play a role.
The Street View integration works fine, though unfortunately whenever I changed the viewing angle, the old image disappeared. (Though that could be a problem with my configuration. I tested Historypin only on my netbook using Chrome, which didn’t make for a solid but rather a slightly shaky experience.) The opacity/transparency of the old photographs can be adjusted, so that one can blend the two images together for even better comparison of the old and the new.
All in all: Great idea, nicely done!