Part of the homepage redesign is that groups of recommended videos are now gone. Now the suggested clips appear in a single ranked list. "Instead of recommending groups of videos to you, we're going to take the best video from the groups and put them in the right order for you," said Johanna Wright, YouTube's VP of Product Management. It uses machine learning and algorithms to figure out your viewing patterns automatically, learning and improving over time. The homepage will also now occasionally surface videos from your Subscriptions, since that's what a lot of people go to YouTube for.

"We believe it's possible to create this personalized experience because we have so many videos in our database," she said. Indeed, YouTube claims that it has about 400 hours of video uploaded to its service every minute. Still, it's challenging work. "We have a billion users, all of them very different. Matching that vast combination of videos to such a varied set of people is really difficult." In the end, they found that people who tried the new homepage tended to spend more time watching videos.

The YouTube homepage makeover is currently mobile only, but even though the desktop home looks the same, it still benefits from the improvements that YouTube has made to recommendations. One of those improvements? You'll start to see newer videos in that recommended list. "We are showing fresher videos with these changes," said Wright. "More videos that have been uploaded in the past hour, more recent videos of your Subscriptions."

To get a closer look at what's going on, you can go ahead and download the update; it should be available on both Google Play and the App Store starting today.