Of course, this is all just politics. It was pretty clear for anyone with even a modicum of political sense that SOPA had simply accumulated too much of a negative connotation to be pushed through without repercussions. With several major websites - including Reddit, the Cheezburger Network, and now Wikipedia - threatening to go dark, the bill's sponsors had no choice but to back off.
For now. It's a rather smart move, since this takes all the wind out of the anti-SOPA camp's sails. In the meantime, the content industry and its politicians can let the SOPA hubbub die out, rename it to something like the "Protecting American Jobs and Loving Puppies and God Act" or whatever and get it rushed through while nobody's looking.
In addition, SOPA's counterpart in the US Senate, PIPA (no, not Pippa, sadly) is still being pushed, so we have to remain vigilant. The content industry and its politicians did not suddenly develop sense - they're just regrouping for a better PR campaign the next time 'round.
As such, Wikipedia has decided to join the blackout protests on Wednesday anyway. The English language variant of Wikipedia will go dark for 24 hours, much like other large sites and companies such as Reddit, Mozilla, the Cheezburger Network, Wordpress, and many others.
We haven't won. We've only postponed our defeat.