title: What does this regex for @mentions do?
body: <p>So I've been trying to figure out what this regex mean - and I'm not getting very far. </p>
  
  <pre><code>(\w+\.?(?:\w+)?)
  </code></pre>
  
  <p>The language is Javascript.</p>
  
  <p>I understand parts of this regex - it looks like it's capturing dots, any word, but forbidding word.word - but I'm not sure?</p>