There are people on this thread claiming that stop and frisk is unconstitutional. It's not. People have to discern between an individual police officer abusing his power and constitutionally accepted police practices.
Also, if someone's behavior truly is "reasonably suspicious" they SHOULD be in a database. If the same person is tracked several times a month, that's an important piece of information of which the police department needs to be aware.
As far as the brass' "quota" is concerned, the number of stops divided by the number of police officers comes out to roughly one per month per cop. If a New York City police officer doesn't see a "reasonably suspicious" individual once a month then the "brass" should be judging him harshly.