@rotomoto When you post video links you have to make them https, by default youtube gives you a link with http. The browsers block insecure content on secure pages.
Edit the post (click the little page with a pencil in the lower right) and change
http://www.youtube.com/embed/9VynhoG6lu0?rel=0 to
https://www.youtube.com/embed/9VynhoG6lu0?rel=0It wasn't a problem in the past but recent browser updates have tightened security settings and are blocking http content on https pages.