YouTube

YouTube is a video-sharing website headquartered in San Bruno, California. The service was created by three former PayPal employees in February 2005. In November 2006, it was bought by Google for US$1.65 billion. YouTube now operates as one of Google's subsidiaries. The site allows users to upload, view, and share videos, and it makes use of Adobe Flash Video and HTML5 technology to display a wide variety of user-generated and corporate media video. Available content includes video clips, TV clips, music videos, and other content such as video blogging, short original videos, and educational videos.

Most of the content on YouTube has been uploaded by individuals, but media corporations including CBS, the BBC, Vevo, Hulu, and other organizations offer some of their material via YouTube, as part of the YouTube partnership program. Unregistered users can watch videos, and registered users can upload videos to their channels. Videos considered to contain potentially offensive content are available only to registered users affirming themselves to be at least 18 years old.

(Source: Wikipedia)

YouTube is a website designed for sharing video. Millions of users around the world have created accounts on the site that allow them to upload videos that anyone can watch. Every minute of every day, more than 35 hours of video is uploaded to YouTube.

Video files can be very large and are often too big to send to someone else by email. By posting a video on YouTube, you can share a video simply by sending the other person a url ‘link’ – that is, the 'address' of the relevant internet page.

When YouTube was created in 2005, it was intended for people to post and share original video content. But since then it's also become both an archive for storing favourite clips, songs and jokes, as well as a marketing site for companies to promote their products.

Nowadays the term ‘viral video’ is common. This refers to a video clip that people have liked so much that they've shared its link by email with millions of others around the globe – in effect, it's spread like a virus. Companies have realised that they can harness this ability to reach potential customers and have created their own YouTube accounts for posting advertisements and other marketing videos.

Film and television companies maintain a tight control over their own content and block illegal sharing of their programmes. However, several now use YouTube to allow fans to see high-quality trailers or repeats of recently aired shows.

(Source: http://digitalunite.com/guides/tv-video/what-youtube)