title: Why uppercase isn't usual in URL
body: <p>I've visited many sites that most of them used lowercase in URLs like</p>
  
  <pre><code>stackoverflow.com/questions
  google.com/webmaster
  bing.com/news
  </code></pre>
  
  <p>Why using uppercase isn't more prevalent? Is there a problem using uppercase in URL? Is this a programming language problem?</p>