At the start, these are a post in the official Google Enterprise blog:
Private sharing in the company
Google Apps users have more control over the content they post on Google+. When you create a post, you can mark it as restricted. Restricted contributions are only available in the company and can never be shared with outsiders, even after the fact. At the same time, with each post, users have the option to share it with specific partners or colleagues outside the company if they wish.
Video meetings involving Gmail, calendars, and docs
With Google Apps, users can have a face-to-face meeting with colleagues or customers around the world, without travel coordination or expensive conference technology. All you need is a device with a camera and an internet connection. With Hangouts, up to 10 people can join a video meeting - via a laptop, smartphone, or tablet PC. As announced in July, a multi-way video chat is now possible through Hangouts and directly through Gmail.
During the hangout meeting, it is possible to open a Google Doc. Colleagues can easily create or change a document together, no matter where they are. And today, users can also add a hangout to a calendar event. So the participants can directly participate in the meeting via the invitation or the calendar entry.
Controls for management
So that users really share their posts only with the people for whom information is intended, administrators can now set standards for limiting posts that apply to the entire enterprise. You can also enable limited Hangouts to facilitate private meetings within the company.
These business features will definitely be free by the end of next year, writes Clay Bavor, Product Management Director, Google Apps. And in the next few months, there's going to be more, such as a special mobile version of Google+ for corporate users and more admin settings.