Quote Originally Posted by Ghallo View Post
So if I were to move all of my accounts to a BNet, but not get the dongle, I would not be impacted except for changing the account name on the login? How does WoW know which account I am trying to log into?
This is correct. Once you have multiple accounts the first time you login to the battle.net account and have SAVE ACCOUNT INFORMATION ticked - it will display a popup box and let you pick the old account name you used to use from the list.

Once you login once, next time it will show your e-mail address in the account name box and a small drop down box with the one you used last saved.