"Google+ really was the template and the critical lesson that helped us believe that this type of project was possible," Singhal says. Hangouts may have taken years to build, but it’s devoid of the siloed approach Google has taken thus far with new products like Wave and Buzz. Hangouts takes what's best about Google — massively powerful cloud services — and marries it to a consumer product.

With Hangouts, Google has created a unifying backend for the future of its real-time products; Singhal describes it as "the single communication app that we want our users to rely on." It's a platform in an almost literal sense — something to build on that's not yet finished. In a way, Hangouts is an extension of Gmail’s product philosophy: to create a conversation between people instead of a chaotic flurry of messages.