The thing that many indie rock followers dispute about are posers and sell outs. first i'd like to say that because a band like death cab sign with a big label, their music is still following the same style as it did in their past records.
the other thing that many followers argue about is posers. the indie rock poser is one of two things... 1-the kid who hears about an indie band on tv and begins acting like they have been a follower from the begining... or 2-the indie obbsessor who reads up on bands they don't even like or that don't sound good just because they're indie and they can be added to their iPod to make said kid look more indie.
that being said indie rock is one of the greatest genres of music ever created and i love it.
Many indie rock bands are characterized by the use of unique or less-popular instruments. Subjectively (since music is subjective), indie rock cds typically sound less "perfect" than mainstream music, which typically grabs the attention of indie rock enthusiasts.
Indie rock is a mixture of many other genres, including alternative rock, folk music, electronica, even pop. It also tends to be very positive music, despite popular opinion.
Others that are popular among indie rockers: The Flaming Lips, The Shins, Bright Eyes, The Decemberists, Wilco, The Magic Numbers, Mates of State, The Essex Green, Calexico, dios (malos), Clap Your Hands Say Yeah, Rilo Kiley, far too many to list. Find a Paste magazine and dig in.
indie although is very competitive and mos hipsters compete for who knows more "un-known" bands.
some indie rock record labels:
2.Underground, somewhat experimental, music. (modest mouse, sigur ros, the decemberists)
3. A tribe of people, hipsters, indie kids who all try to latch onto the next hip band before their friend does.
Avant-guard jazz fan: Sigh...
I know they're on a major label, but they are definitely Indie Rock!