In his recent paper in TESL-EJ, Brian Hutchison outlines the main features of Google+ and says
"Google+ is a feature rich social networking service that provides students with the opportunity to interact with their teachers and classmates outside of class through both asynchronous and synchronous communications. In terms of synchronous communication, the Hangout feature can be used by groups of up to ten students to communicate via text, voice, and video in order to complete such tasks as group discussions, debates, and surveys. Videos of the Hangout sessions can be uploaded to YouTube and viewed by classmates to extend the activities or by teachers for feedback and evaluation. In terms of asynchronous communication, students can share online content they find interesting and useful (such as links to websites and videos) as well as their own personal photos and writings. Once shared, other users are then able to extend a thread or multiple threads of asynchronous communication through the comments they post.
Along with connecting current classmates, Google+ is capable of providing students with access to communities of language learners and educators that exist outside the traditional classroom. These virtual communities are environments that will persist long after an individual class or even an entire course finishes. Instructors can remain in contact with graduating students, students can remain in contact with their classmates, and classmates can be welcomed as new members in an expanding circle of class alumni."