In short: Today, Google made a slew of announcements in regards to search, with it being the 20th birthday of Google Search and all. One of the bigger announcements was around Google Feed, which was rumored be renamed to Discover last week. Now it has been officially renamed to Discover, and Google also said that this stream of news and such will appear below the search box on its mobile website as well. So you're going to get all of your information on Google's mobile website, without even needing the app open on your phone.
There is a new feature being incorporated to Discover here, which includes topic headings, so that you can tap on the heading and check out news under that topic all at once. That makes it easier to read more about a specific topic that you may have been researching already. Google also has a control button on the bottom right corner of each card, so you can control what you're seeing and how often you are seeing it in Discover.
Background: Google Feed, now Discover, originally began as Google Now, way back in 2012. Over the years, it has evolved and while it stopped being Google Now when Google Assistant came out, "Discover" does sound a bit better, especially since you are "discovering" news and other information here. It's a very useful screen that sits to the left of your home screen, and it should get even more useful with the updates announced today.
Impact: This isn't going to affect many people, in fact many will likely not even realize that the name had been changed from Google Feed to Discover. Especially since there really is no rebranding being done, visually here. In fact, it was never shown anywhere to be the "Google Feed" before. But these changes that were announced with Discover should becoming in the next few days.