In July, NYC released arguably one of the most valuable datasets in the country, their PLUTO data (aka their extensive land use and geographic data at the tax lot level). The opening up of this data (with support by NYC’s open data law) is significant, because previously PLUTO data cost $300 per borough ($1500 for all of NYC) for every updated iteration (updated each quarter) and was forbidden from being posted online. Read more here. Last night, BetaNYC hosted a discussion about the value of this dataset and they are hosting a hackathon on this data next Wednesday, August 14th.
PLUTO in geoJSON pic posted above via Andrew Hill/CartoDB.