Today's the day if you try to find something out from Wikipedia, you can't.

Some Internet sites like Wikipedia, have gone dark for the day to protest anti-piracy legislation in Congress.

Instead of the usual Wikipedia page, you'll see a black and white screen with the message: "Imagine a world without free knowledge."

Of course, many people remember when you had to pick up a reference book or an encyclopedia to find something out. But the Internet has changed that, and answers to all sorts of questions (What do penguins eat? Who are the political leaders in Belgium?) are just a click away.

At The Washington Post, their story about the sites going dark carries the headline "What happens when the Internet gets mad." (To be clear, that's the headline on the site's home page. When you click on the story, the headline is "SOPA protests shut down Web sites."

What sites do you depend on for either information, inspiration, humor or gossip? Are there some sites you check out every day, or are you a more occasional and varied surfer? And will you miss Wikipedia today?