The major parties behind the SOPA blackout protests have joined forces to form the Internet Defense League. Not only does the League have their own cat-signal (pictured below), they have defense plans for when new threats against our free internet pop up. Current members include Mozilla, Wordpress, Public Knowledge, imgur, Reddit, Fight for the Future, and more. The way it's designed is that all member websites will get a message from the IDL when a new threat pops up. With the message they'll get an alert-code to put on each member website that tells views to do things like contact their representatives. Member websites can choose whether or not to put the code on their website, so it's not like anything is forced. Basically it's a way to spread the word of a new threat across the internet faster than before.
Just for fun, there are launch parties across the world timed to be the same time as The Dark Knight Rises is released. There will be high-powered spotlights with the cat-signal shining in cities across the globe. If you donate enough, the IDL will try their hardest to find a spotlight for you to rent for a night to help spread the word about the IDL. With smaller donations comes things like small cat-signals, t-shirts, bumper stickers, and other such things.