"On its own, killing @ is a small move. Few other social media networks use @ as a way of indicating who you're talking to. But at Twitter, @ is at the core of a crucial debate within the company about how to get Twitter's user-base growing again. Some people — including CEO Dick Costolo — think the shorthand codes used on Twitter may be deterring new users from joining the site. Unless you already know what they mean, terms like @, #, RT, MT and #FF are meaningless."