How to play Blizzard games in offline mode
More information about authenticator security codes
What to do when getting an error that the Battle.net Account has logged in somewhere else.
Some games require that you add a phone number to your Battle.net account
Instructions on linking your MLG and Blizzard accounts
What to do when a physical authenticator gets out of sync
Information about retrieving a locked account
A BattleTag can only be updated for free once