Mr. Beykpour said one advantage of Periscope was the short lag time between the stream and the ability to send text responses to the person streaming, essentially letting people communicate with the broadcaster in near real time. Periscope also takes advantage of a user’s Twitter followers to rapidly build a potential audience, and the app suggests other active Periscope users as people to follow. In addition, the app lets users store videos for replay or sharing later.
Although Periscope operates independently of its corporate owner — much like the Twitter-owned short-form video app Vine — it has access to Twitter’s money and technical support.
But Periscope has competition, including Camio and — in particular — Meerkat, which appeared this month and has gained traction with consumers and celebrities. In a matter of days after Meerkat was introduced, its use exploded and it soared to become the 177th most downloaded app in the United States and the 22nd most popular social networking app, according to App Annie, a mobile analytics firm. Meerkating, which describes the act of someone shooting a video live stream, is becoming a verb.
Much of that traction came from Meerkat’s breakout popularity during South by Southwest, the technology and music conference held in Austin, Tex., this month, where a number of fledgling start-ups have gained momentum by creating buzz.
Periscope was under development for a year, but Twitter failed to quickly introduce and market the product after it bought the company in January, the people close to Twitter said. That let Meerkat swoop in to take the spotlight. About two weeks ago, Twitter restricted Meerkat’s access to its social graph, which meant that a user’s Twitter followers would not automatically show up in Meerkat.
Success for Ben Rubin, Meerkat’s founder, did not come overnight. He is a founder of Yevvo, another live-streaming video app that made its debut in 2012 yet saw little traction. Eventually Yevvo rebranded itself Air, which also flopped.
Now investors are eager to fund Meerkat. The companysaid Thursday that it raised $14 million from the venture capital firm Greylock Partners and other investors, including the YouTube co-founder Chad Hurley and the actor Jared Leto. In an online post, the Greylock partner Josh Elman said he invested in Meerkat because “it feels like we are at the dawn of a new era for live video.”
“Think of the selfie culture these days,” Mr. Rubin said. “Culturally, we’ve reached the point where cameras are more familiar and people have started to feel comfortable with video.”
Live-streaming video has many applications, including for real-time news. On Thursday, during a fire at an apartment building in the East Village, numerous Twitter users live-streamed the event with Periscope and Meerkat.
For some users, live video streaming has now become almost a daily event. “I like the random, serendipitous nature of it,” said Ryan Hoover, founder of Product Hunt, a San Francisco-based start-up that provides guidance on products from other start-ups. Mr. Hoover said he streamed himself using Meerkat two to three times a week and was an avid watcher of other people’s videos.
He pointed to Jeff Needles, a friend from Twitter. Mr. Needles has recently hosted 24-hour “Meerathons,” in which he streams himself on Meerkat around the clock.
Others entrepreneurs, like Justin Kan, have tried and failed in some forms of live-streaming personal video. His early start-up Justin.tv was a 24/7 live feed of his own life.
“We weren’t able to retain an audience because, really, we just weren’t that interesting,” Mr. Kan said in a recent interview. Eventually, he found success. Mr. Kan sold Twitch, a gaming-focused streaming start-up, to Amazon for about $1 billion last year.
Live-streaming video also poses certain challenges. Some people do not wish to be recorded without their permission, something difficult to prohibit when everyone with a smartphone can freely stream video using the app.
At the start-up incubator Y Combinator’s demo day in Silicon Valley this week, audience members were told not to live-stream the presentations because doing so might violate rules prohibiting general solicitation for funding set forth by the Securities and Exchange Commission.
Live-streaming video’s appeal to operators of sex cams is also obvious. Some of the apps offer settings, such as private broadcasting, that could promote the practice.
Mr. Beykpour, Periscope’s co-founder, said that pornography violated the app’s terms of service and anyone watching a video could report it for a violation.
“Our focus now is to keep it a safe place,” he said.
