Reading through tweets can be daunting. By the time you have read through 20 or 30 tweets, there is a good chance that 30 new tweets have been published. It can be impossible to get through every tweet, especially when many tweets are replicated about the same topic.
In comes Highlights, a fast and simple summary of Twitter of the stuff that is most relevant to you. Highlights are created by gathering tweets from people you are close with, topics and events in your region, and people that are popular among the people you know. If and when you opt into Highlights, you will get up to two notifications per day with your summaries. When you open the notification, you will be taken to the Twitter app where your Highlights will be displayed in a brand new interface.
Highlights will only be available in English to Android users for the time being.
Source – Twitter Blog