If you use Google+ there's a good chance within the last day or so you've been inundated with invitations to join various "communities" on the social network. That's because on Dec. 6 Google rolled out Google+ Communities, which engineering VP Vic Gundotra in a blog post said now offers "a gathering place for your passions."

Already, people are demonstrating their passion for business, which might be good news for you. In theory, these groups might present new ways to interact with your audience, target your marketing, and connect with other like-minded entrepreneurs. All sorts of communities have sprung up, including Makers, Hackers, Artists & EngineersEntrepreneurs, Self-Employed & Small Business, as well as Silicon Valley. The latter was started by tech pundit and columnist Mike Elgan, a huge Google+ proponent who has a following of nearly 2 million fans there.

"Communities solves Google+'s undeserved reputation as a place only for geeks and photographers," Elgan wrote in a Computerworld story. "I've said from the beginning that every interest is represented on Google+. Now, Communities creates explicit spaces where thousands of interests can be easily discovered."

Google+ Communities offers public or private memberships.

A public group can be set up to let anyone join, start threads, and make comments. You can also limit who creates threads to only designated moderators. Private groups, on the other hand, can be set up just for members but discoverable in Web searches, or they can be fully private so that only people with the correct url can find them.

Within a particular community you can look for discussion categories, which is a far cry better than how you used to have to engage on a brand page, says Internet entrepreneur Tom Rolfson, who started a community called HangoutHelp, which helps people understand how to use the popular Hangout video chat feature in Google+ and already includes discussions on how to use Hangouts for business.

"Communities allow much greater interaction than a brand page allowed," he says. "It allows participants to start their own threads as opposed to having to tag onto an existing post by a page manager."

Google+ Communities also lets you start hangouts and plan events with community members as well as share content with that community by clicking the +1 button wherever you are on the Web.

Want to moderate a community around a topic that interests you? Here's how:

Visit https://plus.google.com/communities and click "create community."

  • Designate whether you want it to be public or private.
  • Name your community.
  • Indicate if you want to approve new members who want to join.

As for that persistent idea that Google+ is a ghost town, Gundotra claims that "Google+ is the fastest-growing network thingy ever. More than 500 million people have upgraded, 235 million are active across Google (+1′ing apps in Google Play, hanging out in Gmail, connecting with friends in Search...), and 135 million are active in just the stream."

But as The Wall Street Journal pointed out recently, Google didn't say how much time people are spending on Google+, unlike in June when the company said people spend an average of 12 minutes there per month.

So will it be worth your time? You'll have to experiment to know for sure.

In other Google+ news that affects business users, last month Google announced that customers of Google Apps for Business, Education and Government now can invite up to 15 people to a hangout, compared to the previous 10-person limit.