News from the East Coast of that strange America, where experiments in smart mobs have proved successful. The idea is that groups of complete strangers can be assembled at a precise place and time to carry out a particular task, then dissipate back to their lives without any further ado. The trick is to make sure that those not taking part can't find out the details in advance, so two stages are involved: first, get people into a public place and pass them instructions for what happens next, then go do it. To those not in the know, the effect is totally inexplicable. The smart mob in Manhattan were informed by Web site to meet in one of a group of bars -- which one depended on your birth month -- where a location and action was distributed by a stranger in a certain kind of hat. The location proved to be a rug store, and the action was that, if approached by a salesperson, to explain that everyone present lived together in a huge warehouse and they were looking for a carpet for a... well, let's call it a group activity. Precisely ten minutes after the mob arrived, everyone left, leaving an entirely bemused salesman. Such experiments aren't new by any means -- if you think it sounds fun, read up on the Situationalists -- but prove that you can pull together a large group of people for a particular task in next to no time. But this time, anyone with the nous to google for Smart Mobs can take part, and there's nothing that anyone can do about it. San Francisco, the natural home of the prankster, is feeling a bit put out that Manhattan got there first, and moves are already afoot to pull off something big there soon. As far as I know, nobody's got anything going in Europe -- but if you do feel like making the summer pass just that little more insanely in London, let me know.