It’s old news by this point that ArenaNet had some trouble with hackers and the like managing to get their hands on the account information of a number of players. Well it seems that the company is still paranoid about customer safety and has put up a mandatory password change for all Guild Wars 2 players.
You might have seen it if you’ve logged it recently, there is a red banner at the top of the screen for some players that suggests you change your password. On February 7, 2013, all players who haven’t changed their password since September 12, 2013 will be required to do so before entering the game.
Furthermore, ArenaNet has put up a passwords blacklist that makes it so you cannot use very obvious passwords such as your username or ‘1234’ or ‘Password’. It might be a bit heavy handed, but the change is for the safety of the player themselves, and the developer really can’t be criticized for such a move.
The Official website suggests that if you’re having some trouble coming up with a password you use 4 random common words and put them together such as ‘Correct Horse Battery Staple’. There’s even a small comic linked to the article that’s sort of helpful.