IHT: Flash mobs: summer silliness spread worldwide The MOBS which I first was thinking had to do with "mobs" as in disoderly crowds, is probably more a tongue in cheek punning of mob and mobile because they are one of Rheingolds' Smart Mobs. I liked this comment from the article

Howard Rheingold, who has published a book entitled "Smart Mobs: The Next Social Revolution," thinks flash mobs are part of a larger trend. "Right now, it's just people wanting to do something silly and it's not hurting anybody, so what's the harm?" he says on smartmobs.com, a Web site that is dedicated to his book. "But it shouldn't come as a surprise when this becomes a major outlet of political activism soon as well," he says, perhaps hopefully.