It's not a musical style, indie stands for independent, it's not music that sounds different to traditional music. I personally think that the term Indie is overrated. I really like independent bands over mainstream bands, but, do you think that bands such as Interpol, Kasabian and Franz Ferdinand. should be labeled as Indie ? I really think not, because it's obvious their mainstream success, just because they're British and dont play Metal or Emo, they should not be labeled as INDIE.

The emergence of a large number of independently owned record labels in the wake of punk and new wave led to the term indie, so you are right in that respect. However a lot of the more successful indie labels often had a distinct sound common to a lot of the bands on that label(see Creation, Blast First, Sub Pop,SST and 4AD for good examples) so association between the word indie and certain styles of music arose.
Now though it's all niche marketing. By describing bands as indie, they're being aimed at specific target groups of consumers

Yes, you're right. But Franz Ferdinand's target isnt indie anymore, or is it ?. Haha it's funny, all bands that go mainstream (well most of them) decline musically (Bloc Party,Franz Ferdinand).

I think you guys have it down.

We've done this before.