Fall Out Boy is crap and in fact, the entire emo genre is total crap. No, I'm not going to get into a debate of semantics as to what exactly is emo. Emo to me is dudes wearing girl pants, lead singer has their hair dyed jet black and hanging over at least one eye, and consists of middle class suburbanites whining about how hard their life is.
While other people might dig back deeper, I think it was Simple Plan in 2002 that brought this shit to the mainstream.
Also, I think Nickelback on got radio play in the first place because of a Canadian law.