How flash mobs started

Remember flash mobs? Stay Free! Magazine has an interview with the guy who started them:

"STAY FREE!: I didn't realize it had started out as kind of a con job.

"BILL: Yeah, I wanted it to appear like one of those things circulating around the internet.

"STAY FREE!: If you'd just sent it from the Mob Project, they would wonder: how did they get my email address?

"BILL: Exactly. The original idea was to create an email that would get forwarded around in some funny way, or that would get people to come to a show that would turn out to be something different or surprising. I eventually came up with a lazy idea, which was that the thing would just have one simple, in-your-face aspect to it--there wouldn't be any show, and that the email would be upfront about the fact that it was inviting people to do basically nothing at all."