The New York Tech Meetup signed up over 800 potential volunteers to help build tools on the fly. Perhaps the most successful has been the Sandy Coworking Crowdmap, which helped businesses displaced by the storm find places to set up shop free. The map worked, and a big reason was that the local tech industry excels at spreading information internally. Efforts to reach the larger city have not caught on as easily (in part because many people’s phones did not work in the immediate aftermath of the storm).