For the definition, I will use what I wrote during my last paper analysis, because I really like the simple definition.
Atomized Flash Mob- Put into motion by electronic means, and people do not interact with one another and disperse quickly.
Bill Wasik's Macy's 2003 Mob (The Original Flash Mob!)
http://ofb.net/~epstein/sl/20030617-mob1.jpg
People were organized via email and other means to meet at the NYC Macy's in 2003. They inquired about a 'love rug,' claiming to be in a free-love commune. The cost of the rug? $10,000!
Frozen Grand Central
http://www.youtube.com/watch?v=jwMj3PJDxuo
The group ImprovEverywhere had 207 people freeze in the middle of Grand Central Station in NYC, and were briefed just before the actual flash mob, after being organized at a separate location. They were frozen for only 5 minutes and disappeared in to the crowd shortly after.
Silent Raves
http://www.youtube.com/watch?v=CadjWh2P2Wo&feature=related
People dance to music no one can hear, can be through a shared station or typically their own music or none at all. Numerous videos on Youtube, but only so many that didn't play music over the video.... which kinda ruins the point of a SILENT rave...