Ready to enter the Cabana?

That's what Tumblr calls its new standalone app launching Tuesday that encourages six friends to chat and watch YouTube videos together.

The app is a collaboration between the Yahoo-owned social network and incubator Polyvore Labs. The idea came to life after Tumblr CEO David Karp saw a demo of Cabana by Jason Lee, Polyvore's product management director, in late January. Impressed, Karp asked Lee how fast could they get Cabana to the masses.

"I thought it was really insanely cool. It really resonated with what I've experienced sharing videos with my friends," Karp said. "We pulled our two teams together and hustled to get this built and ready in about two months."

Unlike Tumblr, the site and app where strangers create fandoms to post photos, videos and full-length text posts, Cabana is meant for a tight circle of friends. It comes as Tumblr is trying to capitalize both on the video craze across other social media competitors such as Facebook, Snapchat and Twitter and the popular chat and discussion apps like GroupMe and Band.

Tumblr has more than 340 million users. About half are teens and millennials, according to the company. But it's considered mid-tier in comparison with other social media sites, according to Sensor Tower, a mobile analytics firm.

Tumblr's iPhone app is ranked as the 14th most-downloaded social network app in Apple's App Store in the US, and the 10th most downloaded in the Google Play app store, Sensor Tower said.

Cabana could give Tumblr a bit of a boost, especially among teens and young adults. Cabana's strategy has tested "really well" in surveys with Tumblr users and in-person lab studies among teens, Lee said.

"The younger demographic really took to the spontaneous concept of hanging out," Lee said. "We want to recreate the experience of friends sitting next to each other watching videos and reacting to them at the same time."

The Cabana app is currently available only in English for iPhone users in the US. A version for Android phones is planned for next month. You must be at least 13 to use it.

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