In accordance with Betteridge's Law of Headlines, I believe the answer is a resounding "no."
The unusually virulent meme quickly spread around the Mac blogging world that iMessage will kill SMS as we know it and, going one stage further, to characterize iMessage as "an attack" on the carriers. John Gruber of Daring Fireball went so far as to say he would "cancel my SMS plan as soon as this ships."
But hold on there a second. Is it really that simple?
