The best idea of this nature I've heard was to use taxation to ensure a _minimum_ oil price. As other posters have mentioned, each time the oil price increases, there is a justification to invest in alternative fuel sources / engines / distribution networks / etc. However, when it subsequently collapses again, such technologies are no longer cost-effective (lacking critical mass, or simply being more expensive than oil at its' lows). Investment in alternatives is therefore a bit of a mug's game. With a minimum price for oil that is high enough to sustain the cost-effectiveness of alternatives, there's a justification to make the long-term large-scale private investments required to build alternative fuels to a critical mass at which they become economical. Politically a little tricky, however.

There are a couple of comments like this here, saying it's in YouTube/Google/Flickr/etc.'s interest to fight against this kind of prioritisation. What makes you think that? It seems to me that actually what we're talking about here is that content providers with deeper pockets will serve content faster to Virgin subscribers. That's yet another barrier to entry to any upstart competitors for these companies, and it's in the interest of the big boys to pay up and ensure they own the fast lane. Net Neutrality as I understand it is precisely about restricting the ability of major players to squeeze out smaller, poorer cousins.