The full public release of Google+ brought it to many people, but not all. In fact, one group that was left in the cold were the users of Google Apps, the company’s range of enterprise products. These accounts could not be connected to the new social network.
Now, that has changed, although you’ll need to have administrative access to a Google App account to enable access. As is often the case with new services from Google, the rollout for this functionality is a bit vague. Accounts that have access turned on manually should see Google+ available within a few days.
If you’re confused about how to start, you can check out the official Google+ rollout tips page that will help organizations enable Google+. The steps are simple, and should only take a few minutes to complete.
Once enabled, users will find that they’ve received a couple new features in exchange for the wait. It will be possible for users to share content with people who aren’t in their circles as long as they’re in the same organization as the user. There is also going to be a migration tool that will transfer existing Google+ accounts to Google Apps, but the beta is “a few weeks”.
Otherwise, the interface and functions will be much as they are for other Google+ users, so anyone who’s already at home with the service should have no trouble adapting.
Source: Official Google Enterprise Blog