Ok this may not be as startling as it, but it has made my day.
You know when you want to post a youtube clip but you only wanted to show people a small portion of it. E.g. "HAI GUYS CHECK OUT THE FREE KICK AT 3.45 IN THIS CLIP DURING THE AJAX/TWENTE GAME ITS WELL GD LOL
It can be a bit of a pain sometimes if it is slow loading or whatever.
ANYWAY...I didn't know this until now, but you can put in some guff in the URL in order to start playing at the time you want. A bit like the page marker in a pdf...
Well, I liked it anyway :(