Damn, didn't saw I was cut... I was saying that 
the seller can choose to have the auto-extend 
feature or not. (most use it and it's the default 
I think).

If someone place a bid during the last 10 minutes, 
it reset the countdown to 10 minutes. (Ie: if 
there is 7 minutes left when someone put a winning 
bid, it reset countdown to 10 minutes. If there is 
1 minutes left, it will also reset countdown to 10 
minutes). There is no limit to how many time the 
countdown can be reseted so it may takes hours in 
some cases... (ie: try to win by being the last 
one to gave-up and go to sleep... :)

Cheers,
Yann Stettler