YouTube is a video sharing website. Users create an account and can upload video clips for others to view. There are now millions of clips available, classified into many specialist channels.
Many people use YouTube just for entertainment but the site also contains a huge amount of learning material as companies and individuals upload tutorials on their products or specialist topic.
Google, who own the site, have also made it easy for other web sites to embed YouTube videos into their pages. They have done this by providing an 'API' (Application Programming Interface) to the YouTube database.
With the massive success of the site, there are now many other video sharing sites that cover more specialist topics.
Challenge see if you can find out one extra fact on this topic that we haven't already told you
Click on this link: YouTube