title: Automatic location detection in Ruby on Rails
body: <p>A technical and legal question - what's the best rails gem to auto-detect location of a web visitor via e.g. IP? Down to granularity of state.</p>
  
  <p>And is this an illegal privacy breach?  Why do some sites auto-detect location and others ask for manual zip code input?</p>
  
  <p>Thanks in advance!</p>