April 4, Tuesday
Almost everyday you see a 404 error or Not found message while surfing the Internet. This error occurs when your computer is not able to communicate with a server or server can't find what was requested. Since the decimal form of April 4 coincides with 404, this day has become 404 Day.
April 4 is a special day for Electronic Frontier Foundation, that organizes a day of action against censorship in public and school libraries. According to the Children's Internet Protection Act (CIPA) public and school libraries have to censor and restrict access to the websites, that might include obscene or pornography images, harmful to minor images in exchange for federal funding.