In the five years since its launch, YouTube has been plagued with copyright lawsuits and profit shortfalls, but also won the bulk of video traffic online.
To celebrate its birthday, we look back at five years of YouTube.
February 2005: The YouTube.com domain is registered. The company was founded by Chad Hurley, Steve Chen and Jawed Karim, three former PayPal employees.
April 2005: The first YouTube video is posted called "Me at the Zoo" featuring Karim.
October 2005: YouTube is officially incorporated.
December 2005: The site is officially launched.
July 2006: The first of a flurry of copyright infringement lawsuits is filed by the Los Angeles News Service.
October 2006: Google acquires YouTube for $1.65 billion.
December 2006: YouTube streams about 100 million videos per day throughout the year.
February 2007: Viacom orders Google to pull approximately 100,000 clips of copyrighted material off YouTube. Google complies.
March 2007: Viacom sues Google for copyright infringement and demands $1 billion plus legal fees.
May 2007: The English Premiere League heads a class action lawsuit against Google for allowing copyrighted material to be posted on YouTube.
October 2007: In response to copyright lawsuits, YouTube launches the Video ID tool to check uploaded video against a database of copyrighted content.
December 2007: YouTube grabs 60 per cent of all traffic for video sites throughout the year.
July 2008: A US court orders Google to hand over YouTube user information to Viacom during the legal battle. After a backlash from Google and privacy advocates, the habits of users are shared with Viacom, but not their identities.
November 2008: An agreement with MGM, Lion's Gate Entertainment and CBS allows full-length films and programmes to be uploaded on YouTube.
