Its impact on national and world consciousness will rival and perhaps ultimately exceed that of 9-11.
In a corporate calamity like this one, the most important thing from the corporate perspective is to first, minimize the significance of the disaster and second, to shift blame.
The corporate overlords seem to have lost control of the message entirely on this one.
It's hard to minimize the impending destruction of that heavily populated, economically significant, favored fantasy land of everyone's imagination that is the Gulf. And everyone seems to know who to blame. For example, Rush's meme about "eco-terrorism" crashed on takeoff. Contrast this situation with the Exxon Valdez. In that case, they were able to cover up much of the extent of the damage, at least from the view of the general public, largely because it happened in such a remote area. Nobody really much cared about Alaska. They didn't have fantasies about retiring there on a yacht. Also, Exxon was pretty much able to pin the whole rap on a drunken sea captain. No such luck in the Gulf. Everyone knows that it was deliberate corporate malfeasance, aided and abetted by deregulating politicians, that lay at the core of the tragedy.
As for the effects of this disaster on world consciousness, this could be the blow that ends the public's "abuse cycle" with Big Oil. After this beating, we're maybe finally gonna leave that sonuvabitch for good. We really mean it this time.
And it may be a wake-up call on the environment. The problem with "global warming" as a mobilizing cause is that it's slowly incremental (boiling the proverbial frog), erratic, and taking place in a complex, chaotic, and unpredictable system, the global climate. It's a lot easier to get the point of an oil-drenched bird than it is of a half-degree rise in mean temperature (even though the latter is part of a far more lethal process in the long run).
In short, global warming is pretty abstract. Oil on the beaches is concrete. 9-11 was concrete. People mobilize to concrete threats far more readily than to abstract ones.