Each BattleTag is assigned a numeric ID to create a unique identifier.

Information on logging into the Battle.net application on more than one computer

Battle.net Balance limit info for the Country Change service

Link to the EULA which contains the answer to this question.

How to delete your Activision account

Information about changing the capitalization in your name without changing the name itself

How to swap email addresses between two accounts

This game account is in a different region or Battle.net account.

This game account is in a different region or Battle.net account.

This game account is in a different region or Battle.net account.