title: Facebook Chat limitations
body: <p>My company develop a product for customer support on Facebook and we want to give the representatives a way to contact the customer via Facebook Chat.
  I have read the Chat API documentations and it is not clear whether users MUST be friends on Facebook in order to chat or is it just enough they both installed a Facebook app? more limitations?
  any insight will be appreciated.</p>
  
  <p>Thanks in advance for you answers,
  Yaniv Hakim</p>