Starting in 2014, your Google+ profile picture better be something you like if you have an Android, because whenever you call another Android, that'll be the picture the person will see on their caller ID.
Whatever Google+ accounts that have a verified phone number attached to them will be automatically opted in to this new feature and their phone's will be linked to their + account. Anyone using an Android to call another Android device will automatically see their account's profile picture, whether or not they have each other in their contacts already (so, like, if you have a photo of you downing a 40 for your profile pic and you're calling your boss, you might want to change it.) The company plans to start rolling out the feature in early 2014, so if you want to opt out, go into your Google+ account and unlink your phone number or disable the "help people who have your phone number find you on Google services and connect with you" option here. It might seem a little intrusive at first, but another way to look at it is that you're going to be able to control your caller ID picture on other people's devices, which is kind of cool. Unless you have one of those cutesy pictures of you and your girl for her contact picture on your phone, then you might have to kiss it good-bye.