YouTube is a video sharing site created in 2005. Shortly thereafter, in 2006, the company was bought by Google. The two sites remain largely separate, but online credentials can be linked between Google and YouTube.
Nearly all of YouTube's videos are Flash videos, although the site is moving towards an HTML5 platform, and some videos are already in this format.
YouTube support high definition videos. The default resolution is 360p, but quality up to 1080p is supported, and there are some videos in the 4K format.