According to an article in today's 'Mail : " Every year between 10 and 20 british teenagers take their own lives as a result of bullying . . experts estimate that cyber-bullying accounts for a third of all bullying . . . 
Colin McKeown , managing director of e-safe education . . . ( says ) 
" Any normal thoughts of how we perceive the bully have changed . These are bright , middle-class children who are ruthlessly picking on others , as well as working-class youngsters , and it escalates very quickly " . . 

We're talking about one or more bullies systematically , cruelly attacking their chosen victim / classmate through vicious, anonymous instant-messages , emails or text messages , sometimes posing as a ficticious character and initially befriending their target before 'turning on' them , and sometimes setting up hoax profiles in the name of their victim on sites such as myspace , bebo ,  or  facebook , often trying  to incite others to 'cyber-attack' their chosen target .
Which can range from mischeviously cheeky to concertedly , cuttingly , cruelly insulting  to ' go kill yourself ' , and/or 'we're going to get you at school tomorrow' . 
Like traditional school-bullies the cyber-bullies chosen victims are usually a bit noticeably sensitive , and/or just 'different' in some way .
I do'nt think , and have never thought that all or most teens are either hoodie-wearing hooligans , or  bullies .
But why do a significant minority delight in tormenting their chosen victims ?
Is it  pure sadism  , or because they've learnt  to bully by having been bullied , or that they are so desparate to be  and to be perceived as 'normal' that they subconsciously seek to externalise their horror  of their insecurities about themselves onto others ?
Or a combination of all or any of those factors and/or more ?
It also seems that most cyber-bullies 'get away with it' , without any sanctions being applied to them .