Comcast formally challenged Google’s YouTube, Facebook, and Verizon’s Go90 this morning as it announced the launch of the beta version of Watchable, its widely anticipated ad-supported streaming service.

Videos at the start will be available via iOS, and Comcast’s X1 set top boxes. They will include content from about 30 partners including AwesomenessTV, Buzzfeed, CelebTV, Collective Digital Studio, Defy Media, Discovery Digital Networks, Fast Company, Flama, Future Today, GarageMonkey, GoPro, Jukin Media, Machinima, Maker Studios, Mashable, Mic Media, NBCUniversal, Network A, Newsy, The Onion, Popsugar, Red Bull, Refinery29, Scripps Networks Interactive, Tastemade, TEN, TYT Network, Vice, Video Detective and Vox.

Comcast’s NBCUniversal recently made a $200 million investment in Vox and an equal investment in Buzzfeed.

“We want to continue to connect creators of compelling content with viewers who want to be entertained, and have been experimenting with new partnerships to deliver more high-quality videos from the web, especially to the television,” says the cable company’s Chief Business Development Officer Sam Schwartz in a blog post.

Comcast plans to add partners, and offer ways to personalize and share content.

“As the video industry continues to evolve, Comcast will continue to experiment,” Schwartz says. “We’ll continue to make investments in new media, create different ways for people to watch the movies and shows they love and test offerings that have the potential to attract new audiences.”