title: What is the best way to programmatically detect porn images?
body: <p>Akismet does an amazing job at detecting spam comments. But comments are not the only form of spam these days. What if I wanted something like akismet to automatically detect porn images on a social networking site which allows users to upload their pics, avatars, etc?</p>
  
  <p>There are already a few image based search engines as well as face recognition stuff available so I am assuming it wouldn't be rocket science and it could be done. However, I have no clue regarding how that stuff works and how I should go about it if I want to develop it from scratch.</p>
  
  <p>How should I get started?</p>
  
  <p>Is there any open source project for this going on?</p>