Like mysapce, and then facebook, I've added in a postbit icon so you can share your google + profile account.
All you need to do is enter your profile number. For example, my profile url is:
Code:
https://plus.google.com/112205274167157028883
So I would just enter in 112205274167157028883 into the profile field box.
(click on your own name in google + to get your url.) If there is a ? and anything after after your number, you should trim that off as it is not part of your profile url.