title: Data Structure and approach for @tagging like Facebook and Twitter?
body: <p>I'm thinking about implementing a system similar Facebook/Twitter where, when a user types @ (or another special character), the user can select a username and "tag" them in a post. I know how to write the jQuery for this kind of behavior, but what does the actual data(base) structure look like for this kind of behavior?</p>
  
  <p>I highly doubt the link is stored directly within the database. Since its possible to tag multiple things, what does this structure look like?</p>