title: When to use a key-value store for web development?
body: <p>When would someone use a key-value (Redis, memcache, etc) store for web development?  An actual use case would be most helpful.</p>
  
  <p>My confusion is that a simple database seems so much more functional because, to my understanding, it can do everything a key-value store can do PLUS it also allows you to do filtering/querying.  Meaning, to my understanding, you can NOT do filter like:</p>
  
  <pre><code>select * homes where price &gt; 100000
  </code></pre>
  
  <p>with a key-value store.</p>
  
  <h2>Example</h2>
  
  <p>Let's pretend that StackOverflow uses a key-value store (memcache, redis, etc).</p>
  
  <p>How would a key-value store help benefit Stackoverflow hosting needs?</p>