It depends on how much leverage gets into the system before the burst. Witness the difference between the tech and housing bubble bursts: People were buying tech stocks with the 1:1 margin requirements (because dude! tech stocks only go up!) vs housing which were leveraged by the home buyers at 5:1 - 10:1 (because dude! home prices only go up!) and by the hedge funds at 30:1 (because dude! national home prices never go down!)
I haven't heard a lot of people buying GRPN/ZNGA/LNKD on margin yet. FB might well change the tone though.
It depends on how much leverage gets into the system before the burst. Witness the difference between the tech and housing bubble bursts: People were buying tech stocks with the 1:1 margin requirements (because dude! tech stocks only go up!) vs housing which were leveraged by the home buyers at 5:1 - 10:1 (because dude! home prices only go up!) and by the hedge funds at 30:1 (because dude! national home prices never go down!)
I haven't heard a lot of people buying GRPN/ZNGA/LNKD on margin yet. FB might well change the tone though.