A look at Livetext on Android and iOS. (Courtesy of Yahoo)

Yahoo on Wednesday announced the launch of a new social networking app called Livetext, a social app as defined by what it doesn't do as by what it does.

The app lets users chat one-on-one while streaming video and sending text messages and emoji. There's no voice chat, no group chat and no option to share links to other media. You can't archive or record conversations within the app. Those were all design decisions to keep the app narrowly focused on personal interaction and in-the-moment conversation, Yahoo executives said.

The combination of video and text makes it hard to compare it directly to any other popular messaging service out there. Think of it as a an update on the silent movie. Or, if you prefer, a live gif.

Including audio chat can sometimes discourage people from firing up an app, said Adam Cahan, the company's senior vice president of video, design and emerging products. In a New York presentation streamed online Wednesday, Cahan said that Livetext is designed to be used for when you may not want to talk to someone -- maybe you're at work, in line somewhere or in a crowded place -- but you want to show off your surroundings. Cahan said Yahoo looks at Livetext as a complement to other messaging programs, and as a product that can carve out its own niche.

"People use lots of different kinds of communications tools," Cahan said. "And they're using them in lots of different kinds of ways."

Cluttering up an app with too many features can be a big design mistake, said Arjun Sethi, Yahoo senior direct of product management and growth. Sethi came to Yahoo after his company, MessageMe, was acquired in October. Sethi said that MessageMe got a bit too bloated, and that his team took lessons from that app's development while building Livetext at Yahoo.

Yahoo's mobile focus to date has been more about providing news, video and other information to users in a clean way, finding success with its weather and News Digest apps. Yet apart from its acquisition of the blogging platform Tumblr, Yahoo hasn't shown a lot of interest in creating its own social service.

Cahan, however, said that a good portion of Yahoo's customers think of it as a place to go for communication services, and that Livetext was serving that audience.

The app has been live in Hong Kong, Taiwan and Ireland and will start rolling out to five other countries, including the United States, on Thursday. It will be free and available on Android and iOS smartphones.