If you are not running one of the browsers and versions listed at http://browsehappy.com/ please try upgrading or switching first.

Note: If you are using an IE9 browser in compatibility mode that makes it render as IE7 and IE7 is not supported. To disable see > http://www.sevenforums.com/tutorials/1196-internet-explorer-compatibility-view-turn-off.html

If you are running one of the browsers and versions listed at http://browsehappy.com please do these four things:

1. Try clearing your browser’s cache:

http://www.google.com/support/accounts/bin/answer.py?hl=en&answer=32050

2. Make sure that you have third-party cookies enabled: http://en.support.wordpress.com/third-party-cookies/

3. Try with all browser extensions or add-ons temporarily disabled.

4. Try enabling HTTPS: http://en.support.wordpress.com/https/

If it’s still happening, let us know exactly which browser (and version of it) you’re using by checking here if necessary http://www.whatbrowser.org/ and also post any error reports you get.

I plainly see the youtube in this post using Firefox 19.
http://kassienetteskorner.com/2013/03/05/a-night-to-remember/

If you can't see it then you have a browser issue.