Participate in topical conversations you or your readers might care about by using the appropriate trending hashtag. You can find trending topics listed under the Trends section of the Explore tab when you’re using Twitter on a mobile app. If you’re on a desktop or laptop computer, trends are listed in many places, including the Home timeline, Notifications, search results, and profile pages.
The benefit of including a trending hashtag in your Tweet is that it will be discoverable by people other than your followers.
Join in on eventized reading-related hashtags like #BookLoversDay on August 9 and #ReadABookDay on September 6.