They are currently doing a 24 hour blackout, to raise awareness of SOPA.
It's part of the movement against SOPA, and from what I've heard, it's made 2 (or was it three) of the original co-sponsors of SOPA back out on the whole thing.
If the bill is passed, it will be legal for the government or individuals to sue Facebook. If Facebook is sued, it can no longer host advertisements. Which means Facebook will no longer be making [as much] money.
As impossible as it seems, Facebook can be censored.
And Duude, thats what I was thinking too. But apparently the constitution no longer matters in this whole thing.
All this act is is basically corporate censorship to increase profits, I heard about this last year when it first happened and I was appalled by the naivety that the American government has, if they think the rest of the world will sit there while they destroy half of the Internet then they are wrong