I just enabled OAuth logins via Google, Facebook and GitHub. You may now login (or register) via these 3rd party services if you so desire.
Important note: You should have the same e-mail address associated with our forum as with any of these 3rd party services, or else it will ask you to create a new account for yourself when you log in.
This is also why we don’t allow Twitter-based logins, because Twitter does not associate accounts with e-mails, and so it can not be tied to your existing account.