title: What is the Reason large sites don't use MySQL with ASP.NET?
body: <p>I have read <a href="http://highscalability.com/blog/2009/8/5/stack-overflow-architecture.html" rel="noreferrer">this article</a> from High Scalability about Stack Overflow and other large websites. Many large high traffic .NET sites such as plentyoffish.com, MySpace and Stack Overflow all use .NET technologies and use SQL Server for their database. In the article it says a source in Stack Overflow said:</p>
  
  <blockquote>
    <p>As you add more and more database
    servers the SQL Server license costs
    can be outrageous. So by starting
    scale up and gradually going scale out
    with non-open source software you can
    be in a world of financial hurt.</p>
  </blockquote>
  
  <p>Why don't these sites use MySQL instead of SQL Server?</p>