title: Rails tagging and tag list
body: <p>I saw alot of good tagging plugins but are these plugins really what I want?</p>
  
  <p>I want to:
  - Tag products, users and news
  - Search by tags
  - List all tags like SELECT DISTINCT tag (for a autocomplete tag list and button tags like here on stackoverflow).</p>
  
  <p>I'm thinking of a separated model Tag. What is the best way to do it? </p>