Today, we've enabled an option to authenticate your account with Google. This applies to both new and existing accounts. When creating a new account, you'll notice a new Google button at the top of the forums. When you set up your new XDA account with Google, you'll still need to set a username so that we can register the new account on our servers. Then for the future, you can login with Google at your convenience.

Existing users, too, can authenticate with Google by going to the Edit Email & Password section of User CP. Your existing account will remain unchanged; you can login as usual in the future with your XDA username and password, or with Google.

An important note: In order to use the XDA apps with Google-authenticated accounts, you must set a password via the Edit Email & Password section, using that password and your XDA username to login to the app.