Justin Bieber's fanbase, aka his Beliebers, are notorious for their rabid devotion to all things Biebs. While this is great for Bieber's record and merch sales, it can lead to tragedy, as is the case here.
Internet message board 4Chan's infamous "/b" board is to blame. They began posting up pics of people cutting themselves and claimed they were doing it so Bieber would stop smoking weed. So while the origins of the trend are fake, the results are very real.
Hashtags such as #cuttingforbieber, #cut4bieber and #cutting4bieber started trending on Twitter, with many people from Justin's predominantly pre-teen female fanbase posting up pics of themselves with cuts to their arms.
Let's hope this trend ends quickly and that nobody is seriously hurt.
4Chan is also responsible for the hoax last year which spread claiming Justin Bieber had cancer, and that fans should shave their heads to show support.