Twitter says that the new experience will make it much easier to keep up on what's trending around the social network, with added descriptions for each topic and more. From Twitter:
We know that trends aren't always self-explanatory, so now you'll see a description below each trend. Since trends tend to be abbreviations without context, like #NYFW, a description will make it clear that this trend is about New York Fashion Week. The new trends experience may also include how many Tweets have been sent and whether a topic is trending up or down.
In our short time playing with the updated Twitter app, the experience of discovering what is trending on the micro-blogging service is much nicer before. The descriptions offer much more insight into what that crazy hashtag means at a glance, and the inclusion of the number of tweets that have gone out on a specific topic are interesting to look at.
Twitter says that the new trends section is rolling out to its mobile apps for users in the U.S., but it will expand to more countries in the future. The company is also working on bringing a similar experience to the web, but that's a bit further down the line.