Youtube announced on Jan 27, 2015 that they will use the HTML 5tag as default on it web
site for users of web browsers; Chrome, Internet Explorer 11, Safari 8, and some Beta versions of Firefox!
If you not familiar with the HTML 5 video tag and what that means for you, let me explain. More then likely your web browser (and most of everybody else) is using Adobe Flash to display videos when they visit youtube.com [http://youtube.com]. The problem with flash is the fact that it is a separate piece of software you have to have installed on your system in order to play those videos. HTML 5 has a tag to handle video on its own, and It does it quite well. Another issue with Flash is that the industry is moving away from it, so it only makes sense that Youtube will do the same. There has been support for the HTML 5tag on Youtube for quite some time now, however you had to explicitly enable it for Youtube to send you a page using the HTML 5 tag.
<video width="320" height="240" controls>
<source src="movie.mp4" type="video/mp4">
<source src="movie.ogg" type="video/ogg">
Your browser does not support the video tag
</video>
With a major video sharing site like Youtube.com switching
over their default video player to HTML 5, it will be one of the final nails in
the coffin for Adobes Flash player. It's about time IMHO.
More info can be found here...