This really fascinating article from 2010 predicted and explained Blackberry's imminent demise:

http://mobileopportunity.blogspot.com/2010/10/whats-really-w...

It's super long, but scroll down to the graphs where he shows the declining growth and margins, and predicts that Blackberry sales are going to suddenly fall off a cliff two years later, which is exactly what happened.

I'm going to be paying a lot of attention to what this guy says in future.

(For bonus points, compare these graphs to Apple's current figures -- Apple needs to add a new adjacent category soon, or they are toast. TV/iWatch to the rescue?)