Peter Bergen : The terrorist group soon provided a tweeted explanation of its motives : `` What Kenyans are witnessing at # Westgate is retributive justice for crimes committed by their military . '' Kenya was first major attack in which terrorists provided Twitter commentary . Terrorism has always been about theater , but use of social media takes it further , he says . Comment:
Peter Bergen : Kenya was first major attack in which terrorists provided Twitter commentary . Terrorism has always been about theater , but use of social media takes it further , he says . Comment: