Summary of the signal loss book

For a long time, the BlackBerry phone was exclusive in the hands of businessmen, managers and heads of bank management councils, and then became a fashion that swept the world of youth who were spending the famous BBM application application most of their time. This phone was raised on top of the choices of phone users in the world, then suddenly disappeared and we no longer see it in the hands of anyone, and it no longer fills the phones selling periods like what was before before and remained a puzzling puzzle for the masses until the book "Loss of Sign For BlackBerry phones