youtube.com embeds are broken
On the post listing pages, the expando button creates a video player for posts which link to youtube.com, but when you click play, it shows "An error occurred. Please try again later." On the single post page, the video player does not appear.
www.youtube.com and youtu.be embeds do work. We do not create an expando button or video player for m.youtube.com.
We should replace our old embed code with an OEmbed implementation. For the last several months the url_metadata
table has been collecting OEmbed references when grab title is used, so we should be able to go back and fix many recent posts.