The changes, announced on Tuesday, 24 May in a post on Twitter's blog by senior product manager Todd Sherman, are as follows:
  • Replies - When replying to a tweet, @names will no longer count toward the 140-character count
  • Media attachments - Adding attachments like photos or videos will no longer count as characters within tweets
  • Retweet and quote tweeting - Users will be able to retweet their own tweets
  • Beginning tweets with a username - New tweets beginning with a username will reach all users' followers, eliminating the need to "use the ”.@” convention, which people currently use to broadcast Tweets broadly." 
Sherman said in the blog post: "These updates will be available over the coming months. Today [Tuesday, 24 May], we’re notifying you and our developers, so that everything works as it should when we roll these changes out."

"In addition to the changes outlined above, we have plans to help you get even more from your Tweets. We’re exploring ways to make existing uses easier and enable new ones, all without compromising the unique brevity and speed that make Twitter the best place for live commentary, connections, and conversations."

For more information, visit the website