4chan is an anonymous message and image-sharing board started by Christopher Poole (aka moot) on October 1, 2003. Almost all users post anonymously, and registration is not required (or even possible) for new users. 4chan features a variety of different boards that range from anime, manga, music, random, photography, to adult content. The site helped create such groups as the Anonymous hacking group, created memes such as lolcats and Rickrolling, and hijack Internet sites as pranks.
Because of the anonymous nature of the site 4chan, some of its users have been in the news because of its bomb threats, pranks, hacks, and child pornography. The site has also been temporarily blocked by AT&T and Verizon, preventing all of its users from accessing the site.