part in virtual roundtable style video chats broadcast for anyone to see.
"This small community has grown the feature in lots of creative ways," said Google+ engineering director Chee Chew.
"And they've made one thing crystal clear: when groups of passionate individuals can broadcast live, together, they results are truly remarkable.
UN Secretary-General Ban Ki-moo, the US president, musician Will.i.am, Desmond Tutu and even the Dalai Lama have taken part in "On Air" hangouts in which intimate online gatherings can be openly viewed at the social network.
"Today we're excited to launch Hangouts On Air to Google+ users worldwide," Chew said.
"So if you have something to say-as an aspiring artist, a global celebrity, or a concerned citizen-you can now go live in front of a global audience."
The "On Air" option for Google+ hangouts is being rolled out gradually because "launching millions of live stations takes some doing."
The unique Hangouts feature has been a huge draw at the online community.
Hangouts can be limited to invited friends or opened to anyone.
"We think looking somebody in the eye and communicating in the normal social way we've learned to do over millennia is important," Google+ vice president Bradley Horowitz told AFP in a recent interview.
"We wanted to bring that authenticity back into the equation."
Hangouts have surprised the Google+ team. They have been used for language and music lessons. A stutterers' support group uses them for group meetings, and let bedridden people virtually explore the world.