Many folks know about the free shuttles for those workers who want to live in San Francisco while working at places like Google, Facebook, Yahoo, eBay and Apple out in the suburbs. . It's another perk. I recently spoke to a GISer who was very impressed by Google's transport system. The details of the stops and routes of these essentially private mass transit systems are not public.
The folks at Stamen, who see the shuttles all over the city, tapped foursquare, hired bike messenger to the tail the busses, and tapped their own eyes at coffee shops to find the stops and map the routes.
The routes have quite an impact on the city: they mean more traffic (especially when they use public transit stop locations), shift the value of residentail properties (those near stops rise) and they generally overlap the public system in many ways, even though they are not regulated by the city itself.
- Marketplace (NPR) Dec 26, but the map has been around since this fall