Once again, Park Slopers are putting Twitter to good use, implementing a new service called BusesAroundMe. Following in suit to the ParkingAroundMe service, tweeters can notify their neighbors as to when the next B67 bus will arrive, making for fewer impatient and generally pissy commuters.
This may not be as epic an application of Twitter as, say, bringing a massive earthquake to the Chinese government's attention, but there's something to said for using a globalizing means of social networking to benefit the local community. Sometimes it's the little things that count, like reading celebrity's tweets inside rather than while freezing your butt off at the bus stop.