Snapchat’s long-rumored Discover feature has been unveiled.

The app’s latest addition will let media outlets host channels that cover news, stories and other narratives through videos and photos. Discover stories – which will stitch together photos, videos and ads determined by individual editorial teams – will last for 24 hours before disappearing.

Reports first emerged in August that Snapchat was rounding up media partners for a new content feature that would package stories for the app’s now estimated 100 million monthly users. The lineup at Discover’s launch is impressive. Partnered outlets announced so far include CNN, Vice, Yahoo News, People, National Geographic, Comedy Central, Food Network and ESPN.

Snapchat insists that Discover isn’t just another social media stream that uses backend algorithms to bump stories based on people’s interests or online habits. The app instead will rely on the editorial judgment of its media partners and give users the choice to opt in, rather than opt out. Snapchat’s ads, which debuted in October, follow the same untargeted model: you watch if you want to watch.

“Social media companies tell us what to read based on what’s most recent or most popular,” the Venice startup said on its blog. “We see it differently. We count on editors and artists, not clicks and shares, to determine what’s important.”

Snapchat closed last year with a monster $485 million funding round from 23 investors, which reportedly included Yahoo and Kleiner Perkins Caufield & Byers.

Staff reporter Melissah Yang can be reached at [email protected]. Follow her on Twitter @MelissahYang for the latest in L.A. tech news.