Google are backing down on net neutrality, apparently.

I don't understand what "net neutrality" means, even after a heated^H^H^H^H^H^Hlukewarm debate with a Googler chum a few months back. I mean, it alliterates nicely and sounds kinda cool and Swiss... but what does it mean?

It seems entirely reasonable for, say, my ISP to run extra cables to the BBC if they want to serve iPlayer traffic better. It seems reasonable to me to prioritise videoconferencing traffic over SMTP to provide better-quality video. Are these breaches of net neutrality? Doesn't the internet interpret dodgy traffic policies as damage, and route around them?

I don't get it and lots of smart people I know seem to really care about it... which would seem to point to a gap in my understanding.