Adobe Flash Player
Steve Jobs also claimed that a large percentage of the video on the Internet is supported on iOS, since many popular video sharing websites such as YouTube have published video content in an HTML5 compatible format, enabling videos to playback in mobile web browsers even without Flash Player.
Vimeo
On October 9, 2007, Vimeo announced support for high definition playback in 1280×720 (720p), becoming the first video sharing site to support consumer HD. Uploaded HD videos were automatically converted into 720/30p VP6 Flash video. Since August 2010, all videos are encoded into H.264 for HTML5 support. All videos uploaded before were re-encoded. Non-Plus users can upload up to 500 MB of videos per week, and up to one HD video per week (additional HD videos uploaded within the same week are encoded to SD).