off-topic, but pertaining to the OP's project at hand: the taxono.my project is a jaw-dropping effort...when I saw the custom-map blog post I assumed it was for a big startup, not for an entrant in the NYC.gov data contest.

I immediately submitted it to reddit/nyc and even logged into the NYC.gov site with my FB account to upvote it. From a quick glance at all the other top entrants, this not only seems to have the highest technical merit, but one that seems to have the highest utility and feasibility as well.

http://2011.nycbigapps.com/submissions/5832-taxonomy

Bravo.