They've said that they would rather do a few cities very well than do a bunch of cities poorly. Also, one of the biggest obstacle is finding, getting permission to use, cleaning up, and publishing different datasets. This is much more of a social problem than technological, although it might improve when they have good reference implementations in their initial cities. Right now they have different datasets for each city because they take what data they can get.

The good news is that the journalism grant that funded them stipulated that they have to release their code at the end of the project, so when that comes, each city can make their own Everyblock if they have the will.