title: How to create my own recommendation engine?
body: <p>I am interested in recommendation engines these days and I want to improve myself in this area. I am currently reading "<a href="https://rads.stackoverflow.com/amzn/click/com/0596529325" rel="noreferrer" rel="nofollow noreferrer">Programming Collective Intelligence</a>" I think this is the best book about this subject, from O'Reilly. But I don't have any ideas how to implement engine; What I mean by "no idea" is "don't know how to start". I have a project like Last.fm in my mind.</p>
  
  <ol>
  <li>Where do (should be implemented on database side or backend side) I start creating
  recommendation engine?</li>
  <li>What level of database knowledge will be needed?</li>
  <li>Is there any open source ones that can be used for help or any resource?</li>
  <li>What should be the first steps that I have to do?</li>
  </ol>