We currently have the ability to link our Facebook, Twitter (and Google when I get around to it) accounts to the forum.
To do this, drop down the user menu on the right hand side, and select External Accounts
You'll then be presented with the following:
First, we'll do Facebook.
Clicking on the Associate with Facebook button will take you to Facebook, and request that you associate with an existing account.
Enter your current Forum password into the Password box. This will then confirm you have linked your Facebook account.
For Twitter, do the same. Click on the Associate with Twitter button. You might be asked to log into Twitter if you aren't already logged in.
You'll again have to enter your Forum password to link the account:
Done (until I add Google!)