For many people, Twitter can be a convoluted platform and is difficult to get started as a new user. Their previous efforts to help the "on-boarding" process like the Discover tab, or suggested accounts never stuck.
Today, after recently announcing Jack Dorsey will continue on as CEO, they launched Moments. This media-centric, new way of following an event is actually pretty slick, and may be something that helps attract new users.
A Moment is a group of tweets stitched together around a specific topic, such as the Super Bowl or a breaking news event. These Moments are curated by Twitter, or Twitter partners like BuzzFeed and the New York Times, and primarily exist within a new tab inside the Twitter app, although they can be shared within tweets as well. Moments tend to be multimedia-heavy, with lots of photo and video tweets included, although that isn’t necessarily a requirement.