The Periscope app, like Meerkat, allows anyone to stream live video to a wide audience with their smartphone.
The new app "lets you share and experience live video from your mobile phone" and is "a perfect complement to Twitter, which is why we acquired the company in January," Twitter's Kevin Weil said in a blog post.
The Periscope team outlined a range of possibilities for the service, including how it can turn any smartphone user into a global reporter.
"What if you could see through the eyes of a protester in Ukraine? Or watch the sunrise from a hot air balloon in Cappadocia?" the Periscope team blog said.
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The team said it sees tremendous potential for the app, which is available to iPhone users with one for Android devices in the works.
"Whether you're witnessing your daughter's first steps or a newsworthy event, Periscope offers an audience and the power of a shared experience," the blog said.
Earlier this month, as Meerkat was becoming a craze at the South by Southwest festival, Twitter cut Meerkat's access to some features, which could limit its ability to grow.
In a Meerkat stream announcing the new funding, Rubin called Periscope "a very slick product, a very beautiful product" but that there was room for multiple players in live video.
The funding round was led by the private equity group Greylock Partners, whose Josh Elman joined the Meerkat board.
"There is room for multiple winners," Elman said in the Meerkat stream from a San Francisco park.
"It's not about competition, it's about this massive pie," or market, that's being created, he said.