title: RESTful way to ask for subset of a resource
body: <p>Suppose I have a resource called user_stats, that has things like how many posts, comments, likes, and followers users have. Is there a RESTful way to only ask for parts of that statistics (i.e. for user_stats/3, tell me how many posts and comments this user has, but don't tell me how many follower this user has.)</p>
  
  <p>The reason I'm asking is some statistical attributes can be computationally intensive (yes I'm generating them at query time). So simply not asking for it can reduce workload.</p>