Google+ Sign-In increases conversions by reducing the burden and friction of login—particularly for mobile users—all while helping users keep their accounts secure. With minimal effort, you can add a trusted registration system that's familiar to users and consistent across devices. Google+ Sign-In lets users skip high drop-off registration forms and avoid having to remember yet another username and password. This makes registration faster and more secure, and reduces support costs for forgotten usernames and passwords.
Build on a trusted relationship
Allow users to sign in with the same credentials they use every day on Google with the same sign-in protections users expect from Google, including 2-step verification. It’s easier for users to sign in with their existing Google account than to create and remember details of a new account.
Works with your existing sign-in systems
You can prompt users to sign in to Google not only at signup, but also when they return to your site, or any other time to take full advantage of your site’s social features. And, your users can connect their existing account on your service to Google even if they are already linked through another social service.
Avoid the hassle of creating your own authentication system
Google+ Sign-In mitigates data-breach risks and reduces the burden and costs of identity security. The Google authentication window creates a trusted link between you, your users, and their Google account.
Learn more about your users and their friends
With a user's permission, Google+ Sign-In lets you improve your service by giving you access to their basic information from their public profile and the list of people in their circles.
Give users more choice
Allowing users to sign in with Google lets them select which identity they want to use in your app. By offering this choice, users are more likely to feel at ease with the decision to sign up for your service, improving conversions.
Improve sign-in conversions
Incremental authorization is a way to ask users for the right permission scopes at the right time, versus all permissions at once. When users see these requests when it makes sense, they can better understand how their info will be used. Asking for consent in context can reduce friction and lead to more completed sign-ins and an engaged audience.
Google+ Platform Insights provides meaningful analytics to optimize your Google+ Sign-In integration. You can see aggregated data about how many people have signed into your app with Google, including active users by day, week, and month. This information helps you understand the overall health of your integration.