Heh, the comment right above it :p

http://youtu.be/p_7Qi3mprKQ vs a query string v= which doesn't have the /
To be fair I didn't notice it either until you brought it up.

parsedUri.directory becomes "/p_7Qi3mprKQ"

Which means embed urls are "/embed/p_7Qi3mprKQ"

I think I'll add a comment about the embed url.