Google only just today announced their Google+ sign-in features that are opening up to app developers, but TuneIn Radio is one of the first out of the gate to implement it. Much as they were involved early on with Jelly Bean expandable notifications, the extremely popular radio streaming app is in on the ground floor with Google's latest features.
To the user, it's exactly the same process as signing in via Twitter or Facebook, without the necessity of course to enter any login details. You choose which of your Google accounts you wish to sign-in with, and that's it. You're also presented with a check box allowing you to restrict who has access to content you share on Google+ -- although sharing something only you can see does seem a little, well, pointless.
Google+ sign in isn't the only new feature in this update either. TuneIn Radio will now integrate with your calendar, so if you don't want to forget about that big