For people like Sara Rreese, Wikipedia is indispensable.
"Composers, people, actors, countries - whatever you need to know, you go to the Wikipedia," she said.
But for one 24-hour period, Wikipedia will close its virtual doors in protest to two pieces of national legislation, a decision that users say will have a large impact.
"My fiance is in college, and he uses it as a reference," said Monica Kroger.
"I think a very important source of knowledge would be taken away from me and my family," said Aditya Bhandri.
The U.S. House of Representatives bill is called "Stop Online Piracy Act" or SOPA, and it's PIPA in the Senate: Protect IP Act.
"What these bills will do is require U.S. internet service providers to pretend that these allegedly pirate websites don't exist, and they'll sort of virtually disappear from the internet," said CNet Chief Political Correspondent, Declan McCullagh.
The film and recording industries support the legislation, as well as CBS Corporation, parent of CNet and CBS News, but some internet companies, like Wikipedia, and privacy advocates are incensed.
"It's the free speech implications of this," McCullagh said. "It's like saying there are a few bad books in the library, so we'll just lock the entire library."
Dozens of other companies, like Reddit and Boing Boing are joining Wikipedia in protest. Also, Google plans on a homepage protest link.
"You could have tens-of-millions of phone calls to the U.S. Congress in one day," McCullagh predicts. "This has never happened before in the history of American politics: this direct, internet-inspired action."
One internet giant, Twitter, will not be joining the blackout. In a tweet, CEO Dick Costolo called Wikipedia's decision "foolish."
Wikipedia will be dark until midnight eastern time.