1. Where did the idea of the collective come from and how long has it been in existence?
The Collective website has only been around for a few months; November/December of 2007.
The concept? That's been around for as long as I can remember. You can say that the counter-culture movement of the sixties made the idea popular, but they didn't quite invent it either.
To answer that would be a philosophical question, something like: "Is a man taught generosity, or is he born with it?". Generosity and greed are two conflicting emotions that we all have, yet our lives are completely dominated by wealth and the acquisition of it. Somewhere along the line, the generous people must've lost some sort of battle with the greedy people.

What I call 'the collective family' is the spirit of giving that lives on through all of us and unites us through a common bond, something given to us through the smiles of our grandfathers and the gifts of our uncles.

But, if you don't feel like being philosophical, the idea came around directly through the actions of the RIAA and the music industry. If they really don't want us sharing their music, then why should we? They can go to hell; we'd much rather be sharing music that wants to be shared.