We have added Google+ authentication option in response to Google's announcement that it will stop supporting Open ID in April, 2015. While currently both, Google+ Sign-In and Google-based Open ID authentication are supported, Google account users are encouraged to start signing in with Google+ and to notify us of any issues. There is no need to re-register, simply click on the Google+ sign-in instead of the Open ID when signing in. Detailed instructions are available here. There is no change for people using Yahoo or other Open ID providers.