title: Are WCF services stateless by default?
body: <p>I've got a simple WCF service that lets clients/consumer applications log in by providing a username and password. If both the username and password are correct, the WCF service provides the client with a GUID. The GUID and the username are then stored as a key/value pair within the WCF service. From here onwards, the client sends their GUID with every request as a means of identification.</p>
  
  <p>Since I'm storing the key/value pair in a Dictionary/Hashmap, this approach would only work if the WCF service is stateful. Question is, are they stateful by default or is there something I have to do to make them behave in that manner?</p>