Whenever a new Web trend comes along, people ask, “What is the point of this?” If millions of people are using something, there has to be a reason. In our What Is the Point of… series, we’ll explain it to you.

This week, we’re asking, What is the point of Google+ Hangouts?

Who Hangs Out On Google+?

It hasn’t exactly taken over the world yet, but Google+ has become the social backbone of all Google’s services. If you “upgrade” your Google account to Google+, as more than 200 million people have, your profile becomes the way people find you in search and communicate with you across the Google-sphere.

Google wants plus.google.com to be your browser start page. If you’ve added friends and smart people to your circles, the page can be a constant source of updates and new information. Given that most people already happily find this service on Facebook, results on Google+ may vary.

But even if all your friends are Facebook loyalists, Google+ offers a killer app that makes it worth your attention. Based on YouTube’s massive infrastructure, Google built Google+ Hangouts, a virtual space that feels like a real place with real people in it whom you can easily meet face-to-face. Hangouts is one of the few Web applications that does justice to the word “social.”

How To Hang Out

A Google+ Hangout is a video chat that can host up to 10 people at a time. It appears as a live event in the Google+ stream, so people can join in if there’s room. You can also switch the Hangout into On Air mode, so anyone in the world (seriously) can watch live via YouTube, even without being on camera. Hangouts On Air are also saved as YouTube videos to watch later.

Anyone on Google+ can start a Hangout. You can post it publicly, so anyone with the link can join, and anyone following you on Google+ can see an invitation in his or her stream. You can also post the invitation to specific circles or individuals only.

You can use Hangouts just to chat with friends, family or colleagues. But it’s also really fun and not (very) creepy to just hang out with whoever’s around on Google+ sometimes.

Hangouts have more potential than text chat. There are apps to make Hangouts more amusing or collaborative. It also works great on mobile devices. With the power of Hangouts On Air, Google has been able to host vast, live media events such as a Hangout with President Obama.

We also host ReadWriteWeb Hangouts all the time. We’d love for you to join us.