In 2005, when SM said they were going to debut a 13-member idol group everyone said "it's going to be a flop!"; now, almost 10 years after there are several successful groups in the industry, and I bet you already know most of them.
Super Junior (2005):
EXO (2012):
Girls' Generation (2007):
Nine Muses (2010):
Topp Dogg (2013):
ZE:A (2010):
