OK, so I received an email from Facebook:
" Dear Developer,
As part of our continued efforts to migrate all apps to OAuth 2.0, we opted in all apps using the new JavaScript SDK to OAuth 2.0 this afternoon at 11am PT and reverted at 1:30pm because we noticed that your app has not migrated. Please ensure that you have set the oauth param in FB.init to true and that you are using FB.getAuthResponse to obtain the access token.
Read more in the OAuth2 migration announcement, updates to the new JS SDK blog post, or our JS SDK docs.
If your app was affected today, please ensure that you have made these changes by December 13th, 2012 to avoid any disruption with your users.
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