Thanks to a neighbour I learned about Sanborn Maps, an amazing historical resource for maps of American cities. The Sanborn Map Company drew maps of American cities from 1867 to 1970 for sale to the fire insurance industry. They're incredibly detailed drawings of every building's shape and structural details with annotations of nearby ovens and fire hydrants. There's a significant collection of these maps at the Library of Congress, since digitized by ProQuest and often made available for online PDF download via your local library. Above is an animation of my half block (Church & Clipper in SF) from 1900, 1914, and 1950. All the old 1900 buildings survived the earthquake and you can see the whole block fill in around 1914. No major changes in 1950 except my house and the one behind me which were rebuilt in the 1930s. Still don't know why.
What I find most interesting are the ephemera, the sheds and workplaces. In 1900 my house had a big hen house, behind me was a French laundry, and the block had three windmills pumping water. In 1914 my hen house had turned into a third apartment, the laundry became a bakery (along with two others on the block) and the windmills were all obsoleted. And by 1950 my house is entirely new, the bakeries are all gone, but now there's a print shop in someone's back yard.
There's an enormous amount of data about American city development, the problem is it's all locked away on paper or, if you're lucky, microfiche. It's great that we have our libraries and companies like Google and the Internet Archive doing so much archiving work, but we've a long way to go before all this data is digitized and indexed.