Twitch has recognized a recent security breach with some of their user accounts and they have acted quickly to protect all Twitch users account information. When you log on now, don’t be surprised to see that they have suspended all user passwords and all stream keys. Also if you used your Twitter or YouTube account to associate them with your Twitch account, they too have been deactivated and you must reconnect and authorize those accounts too.
There isn’t much intel on what the hack exposed or who was hacked but we suggest changing your passwords often, such as every three months, just to keep your information safe. Twitch will “communicate directly with affected users” on any additional steps that they can take to prevent this from happening again.