title: CDN vs Homegrown Caching
body: <p>My understanding of a CDN (like Akamai or Limelight) is that they are heavy-duty caching services.</p>
  
  <p>I also understand that they are very expensive. So I'm wondering why I can't just create my own cluster of replicated caching servers (using, say, EhCache or Memcached) for all my web app's caching needs (images, URL hits/responses, Javascripts, etc) and basically get the same thing?</p>
  
  <p>In essence, from a developer's perspective, what are the benefits (technical or otherwise) of paying a CDN vs. just using your own caching solution? Or, if I have completely misunderstood what CDNs are, please correct my understanding! Thanks in advance!</p>