What does the YouTube page https://www.youtube.com/html5 do for people? Is it just information? Does it configure something on YouTube itself that recognizes a given computer or browser and causes YouTube to uses html5 playback when that computer or browser visits YouTube? (If so, does this work if a person doesn't log-on to a YouTube account ?) Does the page alter something on the users machine or browser so that the machine or browser uses html5 playback when it accesses YouTube? That page on YouTube is often suggested to people who are having problems viewing YouTube videos with various browsers. But I have yet to see an explanation of what that page does - if anything.