A great example is that of Wall Street Journal . They have the Twitter name @WSJ . It’s only three letters and their logo also has these letters. It’s also unique. All these factors make it easy to remember. As these letters are in their logo which can be found both on their website and their Twitter profile, it promotes their brand. The next time someone Tweets something from their website or Tweets something about them it should be extremely easy to remember those three letters and mention them in the Tweet. Therefore they will get more mentions and followers in the process.