Yahoo launched a video-viewing iOS app, Yahoo Screen, on Monday, the first major app launch from the company's 10-month-old mobile engineering office in New York City.

The app is a portal to content from Yahoo's video partners, which include ABC News and Martha Stewart, and to its growing portfolio of original content. In conjunction with the app launch Monday, Yahoo is releasing episodes from eight new comedy series, featuring the likes of Jack Black, John Stamos, Ed Helms and Cheryl Hines.

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They will be joined by a variety of licensed content, including 5,000 clips from the last 38 years of SNL, which Yahoo secured streaming rights for in late April.

Yahoo is also announcing on Monday that it has signed a licensing agreement with Viacom, bringing clips from Comedy Central shows The Daily Show With Jon Stewart and The Colbert Report to Yahoo Screen. In October, clips from South Park will join the service as well.

Though Yahoo specializes in short videos and clips, which are ideal for web consumption, its Screen app is designed to "feel like a lean-back TV experience," said Robby Stein, a former Stamped co-founder who now heads up Yahoo's mobile engineering office in New York, in an interview with Mashable last week. Streaming video plays the second the app opens, as if you'd just hit the power button on your TV set.

Content is organized into horizontal "channels," including rows for comedy, celebrity and sports. You can access content from each channel without leaving the home screen: Just swipe to the right to explore more videos.

In addition to topical browsing, you can also search across videos. A search for "Obama" yields a screen full of clips from the AP, Reuters, ABC News — and the list goes on. All videos can be shared through Facebook, Twitter and e-mail.

Yahoo Screen will launch without ads. Bart Stein, another Stamped co-founder who now serves as product manager of emerging products and technologies at Yahoo, said the company is still "looking at the most engaging ad format[s] for Yahoo and our users over time."

Several other features are also missing. Videos can't be saved for viewing offline, and unlike many of Yahoo's recently revamped products, no personalization capabilities are available. But Robby said content will eventually be more personalized based on past viewing behavior. An Android version of the app is also on the way, Bart said.

In addition to the mobile app launch, Yahoo Screen has been redesigned for the desktop in a format that closely resembles its mobile counterpart. Where a user would swipe or tap on the iOS app, a desktop user navigates with the mouse.

"Yahoo is a mobile-first company now," Robby said. "We think about how products work on mobile devices first, and how they work on desktop second."

The app is fast, elegant and easy to use, and seems primed for a much larger catalog of content. (We suddenly find ourselves wishing Yahoo acquired Hulu after all.) Given the string of licensing deals Yahoo has signed over the past few months, it seems fair to expect more, though the company would have to overtake the likes of YouTube and Netflix if it wants to become the ultimate portal for video.

Images: Flickr, Sully213