It would be great that flash videos would reproduce right off without manual configuration. An official update that installed Greasemonkey with Youtube Perfect-Embedded and Youtube Perfect-Preview would give better usability to Trisquel. It works great.
A message from flop333:
Greasemonkey lets you visualize embedded videos with Totem and works well on youtube (install in from synaptic, for example). You need to install two scripts for Greasemonkey:
http://userscripts.org/scripts/show/38074
http://userscripts.org/scripts/show/46219
Information courtesy of aitux on the english forum (http://trisquel.info/en/forum/swfdec-092-and-youtube).
Fixed with flashvideoreplacer.