title: Why exactly isn't MEF a DI/IoC container?
body: <p>It's been said on the blogosphere and by Microsoft themselves that MEF isn't another IoC container.</p>
  
  <p>OK...but why? It seems the same to me. Maybe it's not as good as Unity or <a href="https://en.wikipedia.org/wiki/Castle_Project#Features" rel="noreferrer">Castle Windsor</a>, but it still fits the definition, doesn't it?</p>
  
  <p>Why isn't MEF an IoC Container like Unity or Castle Windsor?</p>