I previously posted a diary on video embedding on Daily Kos diaries where I couldn't figure out how the You Tube embedding option wasn't working. It appears quite a number of other Kossacks have been dealing with the same issue as I have.
Now here's a solution (until You Tube gets off its high horse and changes the embedding option back to the way it used to be):
For any You Tube video, if you see a URL that is missing an http in front of it, go ahead and add it to the URL and copy the embedded code as it's intact and paste it to the Kos diary (or comment) you're making.
Example: Here I'm embedding the following video
1) Go to the embed option
2) URL says /www.youtube.com/embed_Kvspzvarfs
3) Type http: in front of the /www.youtube.com/embed_Kvspzvarfs with no spaces in between.
4) Select the entire embedded code
5) Copy and paste to comment or diary
Simple. I know you guys will likely go to the Daily Kos help desk but since lots of people are facing the problem, I thought I'd do the community a favor per my previous diary.