YouTube Changes Embed Code to HTML5-friendly iFrames
Previously YouTube allowed users the choice of using Flash code or HTML5-friendly iFrame code. The new version, however, makes that choice for them, and defaults to the iFrame version. Although the appearance of the video will remain the same, the changes will likely have an effect on SEO.
When the iFrame is rendered in the browser, it displays the newer YouTube player (version 3), which features additional functionality. Along with this new functionality, the option for changing border colors has been removed.