Twitter is introducing Bookmarks, an easy way to save Tweets for quick access later. In addition, with a new "share" icon on every Tweet, you'll be able to bookmark a Tweet, share via Direct Message, or share off of Twitter any number of ways.
To bookmark a Tweet, tap the share icon under the Tweet and select, "Add Tweet to Bookmarks". To find it later, tap "Bookmarks" from your profile icon menu. You can remove Tweets from your Bookmarks at any time. Also, only you can see what you've bookmarked.
Bookmarks are now rolling out globally on Twitter for iOS and Android, Twitter Lite, and mobile.twitter.com.