If you access YouTube on a web browser such as Chrome, the videos will now use the HTML5 player by default. Google announced this move today, while also revealing it is "deprecating" the old Flash-based embeds and Flash API from YouTube.
In a blog post, YouTube stated that advancements in the use of HTML5 for video playing, along with improvements in the web coding standard in many browsers, have allowed them to make the move to get rid of the old Flash standard. They stated:
These advancements have benefited not just YouTube's community, but the entire industry. Other content providers like Netflix and Vimeo, as well as companies like Microsoft and Apple have embraced HTML5 and been key contributors to its success. By providing an open standard platform, HTML5 has also enabled new classes of devices like Chromebooks and Chromecast.
People who embed YouTube videos on their websites are now being encourage to use the more modern iframe API going forward.