by: Bernhard Warner | Bloomberg Businessweek

Uh oh. Teens are growing tired of Facebook and YouTube, new research (pdf) shows, a falling-out that has the potential to trigger a wide-ranging effect on retail, fashion, gaming, and other youth-oriented industries.

According to Piper Jaffray (PJC), while Facebook and YouTube are still considered the most important social media destination for teens, their popularity among this fickle demographic has fallen precipitously since this time last year.