Google is making it easier for app developers to connect with users on its social network through Google+ Sign-In, a new feature that allows people to sign into third-party apps using their Google+ credentials.
The authentication system lets Google+ users sign into outside apps with their existing user name and password, and includes Google's two-step security verification when logging in from a mobile phone. The user's Google+ info is automatically pulled into the app with the tool, which is available to Android, iOS and Web application developers.
"It's simple, it's secure and it prohibits social spam," said Google+ product management director Seth Sternberg Tuesday in a blog post.
The sign-in feature is aimed at making Google+ and Google's developer platform more widely used, while other social networks like Facebook and Twitter already offer easy access to outside apps.
The feature works like this: If a person is signed into Gmail, YouTube or any other Google service, the user can sign into the outside app with the same credentials. The person then lands on a Google+ permissions page outlining the data that the person is sharing with the app, which can be customized.
Google is highlighting Sign-In's content-sharing controls as a major feature of the service. The functionality rests on the premise that users might want to share certain types of app content with some people in their network but not others.
People might want to share things, for instance, like high scores on a gaming app with the world, but keep other things, like data from a fitness app, to themselves, Google said.
The sharing controls are also designed to encourage more engagement with apps on Google+. When Google+ users share an app that uses Google+ Sign-In, friends will see a new kind of "interactive" post in their Google+ feed. Clicking on the post will take the person inside the app where he can buy, listen to or review what was shared, Google said.
Google+ Sign-In is also designed to simplify the app installation process across desktops and mobile devices. When Android users sign into an app on the desktop, they can install the mobile version of the same app on their Android device with a single click, Google said.
Google seems to be positioning the Sign-In service as an easier way for Google users to engage with apps and to better target who they are sharing with on Google+. The feature also functions similarly to how people can already sign into apps using their Facebook and Twitter credentials using those social networks' developer platforms.
Still, Google's Sign-In developer platform comes more than a year-and-a-half after Google's launch of its Google+ social network.
Developers currently using Google+ Sign-In include OpenTable, Flixster, the Guardian and USA Today. Tuesday's rollout is an initial release, Google said. "We're just getting started," said Sternberg.