Communication tools that people use heavily enough to care about acquire a context beyond just "Who I can communicate with". As the recipient, for the majority of my routine communications I get information from medium > sender > content, even though all ways of reaching me just make my phone jingle.
The series of decisions that results in me calling someone is so radically different than the one that results in IMing them that I'd never find it useful to start with a person and then decide to IM or call.
I'm about as often in the task-oriented position of thinking "I should call someone" or "I wonder who's awake on jabber" as the person-oriented position anyway.
A phone could have a list of people and clicking could activate the preferred communication method. It might have smart algorithms that even choose the people you'd be most likely to communicate with in the context you're in. So the aim of this UI idea, saving keystrokes, gaining flexibility could be gotten even in your context.
The problem is that even if the aim is achieved, if the keystrokes could be saved and the flexibility increased, it would not benefit someone that much. Most people aren't speed typing, most people already can remember all the people they want to communicate with already, etc.
UIs have stayed at the point they're at based on the "good enough" principle. UIs may not be optimal altogether but optimality only matters when you're on the "critical path" and with a UI, thinking may be the critical path and keystrokes, associations and etc may come a distant second.
Well, the medium is of course the message — but that doesn't mean that we can't encourage users to think of the medium of electronic communication as a single thing. We know it's all just some structured data being bounced around, why not make that clear?
I think that would be a great thing, and would be the main benefit of pursuing the approach the author is arguing for.
The series of decisions that results in me calling someone is so radically different than the one that results in IMing them that I'd never find it useful to start with a person and then decide to IM or call.
I'm about as often in the task-oriented position of thinking "I should call someone" or "I wonder who's awake on jabber" as the person-oriented position anyway.
tl;dr: The medium is the message