If Hangout draws enough interest from developers, the video platform could enable Google+ to offer potentially richer social experiences than its number-one competitor, Facebook.

"Video adds a very intimate and engaging experience," said Blau. "It's somewhat different from typing your status or sharing a link with your friend or liking something."

Owyang said the ability to communicate in real time could also prompt users to spend more time on Google+, a metric in which the social network has thus far fared poorly. Visitors spent an average of three minutes per month on Google+ between January and February, compared to six or seven hours on Facebook, according to .

"People are dipping in and out of Facebook," he said. Because Google+ users tend to be more tech-savvy, Google "is probably playing to their strengths in that regard, with people who are always online."

The apps available now on Hangout are , , , ,  by Bravo and Google Effects.