I noticed a few days ago that registering with a Google account was no longer working on this site. We use the Janrain social sign-in toolkit, and a little investigation showed this was all to do with the change from Google to Google+ accounts (some boring yada here). I think it works now, and we also enabled sign-in with Disqus and OpenID too (not that anyone knows their OpenID, but it's kinda geeky).