I was looking for an exchange to trade doge on and tried to sign up at http://bter.com after following that link from coinotron, site has issues I would guess as it wouldn't accept the passwords I gave it to create an account but sort of logged me in anyway without even creating an account! 
You can use Vircurex now to trade Dogecoin, but wait for Doge to be added on mcxNow which is much faster and more secure than any other exchange.