First came social sharing, then came social login. By now, the vast majority of internet users have encountered an online site with the “Log in with” button alongside a social network logo, allowing them to sign in using their network credentials.

There are plenty of benefits to using social sign-in, for both users and brands. For online companies, social sign-in provides a portal to a user’s social data, while for consumers, it’s faster than filling out yet another web registration form and easier than having to come up with—and remember—another set of login credentials.

But still a significant percentage of users don’t click.

via Privacy Concerns Keep Users Away From Social Sign-In – eMarketer.