So, embedded YouTube's videos and logged in https://www.youtube.com/feed/subscriptions?flow=2 are currently showing:

"500 Internal Server Error

Sorry, something went wrong.

A team of highly trained monkeys has been dispatched to deal with this situation.
If you see them, send them this information as text (screenshots frighten them): ..."

and "Sorry - there’s a temporary issue loading your subscriptions. Please revisit this page shortly to try again."


http://reddit.com/r/youtube, http://productforums.google.com/forum/#!forum/youtube, etc. confirm it.

At least we still have other video hosts like vimeo.com. I wonder how much I missed since before 1 PM PDT.