Google+ hangouts is connected to what other social media site?

Google Plus is the social media site that is connected with Hangouts.

To add, Google Plus is an interest-based social network that is owned and operated by Google. Google's fourth foray into social networking, experienced strong growth in its initial years, although usage statistics have varied, depending on how the service is defined. 

answer; i believe the correct answer is ( a expression) plz check first.good luck