Another factor chipping away at teenage retailers may be the shifting priorities among young people. Where clothing was once the key to signaling a teenager’s identity, other items may have become more important and now compete for their dollars.
“Probably the most important thing a teenage boy has is his smartphone,” said Richard Jaffe, an analyst at Stifel Nicolaus. “Second, is probably his sneakers. Third, maybe, we get to his jeans.”

From the NYTimes on the struggles of clothing retailers focused on the teen market, like Abercrombie and Fitch.

It makes sense that if we spend more of our time immersed in the world of information that we'd shift some of our signaling efforts from the physical world to the digital one. From purely a leverage perspective, shooting, editing, and posting one photo of yourself to Instagram or Facebook or carefully crafting one tweet or Facebook status update might reach more of an audience than, say, the outfit you choose to wear that day.

It both amazes me and doesn't surprise me at all how many people choose a custom cover photo for their Facebook timeline. Think about how many otherwise modest people you know who retweet tweets that are complimentary of themselves. In the shift to digital signaling new norms have formed.