At one point does a band become mainstream?

When one of their songs gets used on a TV ad.

I think when many people start to know them. Since they did release In Rainbows and The King of Limbs by themselves, their both mainstream/indie. But mainstream means a lot of different things, technically their both mainstream and indie. I just think of Radiohead as one of the bands that are still making albums I love, throughout the years, instead of letting the mainstream get in their heads.

Not that I think I'm a musical expert or anything, but I always thought that a band becomes mainstream when they gain a lot of airplay or attention, not really if they're mentioned in a song :/

On a different note, did she really mention them?

EDIT: I can't even figure out how I should react to that.

radiohead is obviously mainstream. they had radio hits. they've won multiple grammys. they have multiple #1 albums. it really doesnt get much more mainstream. i dont need katy perry to tell me that.

anyway, i really dont see the point in nit picking or trying to draw a clear line in the sand about this. if a lot of people have heard of them they are mainstream.

I think a band becomes mainstream when at least one of their songs gets a lot of airplay, and if you ask an average music listener if they know who it is and they do. I'm not talking about someone who listens to music most of the time, but like has an ipod, listens to the radio when they work out, etc.

When I hear a RECENT song by them on the radio.

There are plenty of bands who were mainstream and then fall back into the "indie" category.

using fact i'm pretentious. as an occasion, I knew who adolescents team have been a pair of years earlier continuously youthful so I accuse them of being sellouts while the music have been given known. thankfully, they have been one hit wonders. same went for Vampire Weekend. while they exploded onto the mainstream, I gave them the tall poppy syndrome. Why? i'm pretentious over the reality i understand those bands earlier you probably did :D

Hard to say there is a mainstream these days.

When they have over 50,000 listeners on Last.fm