When someone knocks at our door and we let them into our home, are we not extending them a permission, a privilege? Are we not offering them our trust?
Isn't logging into a site using our social media login the same privilege? We expect a third party website to prove that they are worthy of this privilege, and they can be trusted.
Sadly though, all these notions vaporized when I tried to login via twitter to add a comment to inc.com. Why do they want to 'Update my twitter profile' or 'Post Tweets' on my behalf?
When we design a web, mobile or any other experience that utilizes a Social sign-on, its probably important to remember how fragile that gesture of trust is.
In a world where online privacy is under a constant assault, trustworthiness matters....even more than ever.