title: Use of GUIDs as id in public facing data integration web service
body: <p>To put the question into some context, the system exposing the web service uses GUIDs internally as identifiers for all entities.</p>
  
  <p>In such case, when designing a public facing data integration web service (used mainly for importing or exporting data from the system to other, external systems), what would you consider as pros and cons of using the internal identifiers in the interface of the service? </p>
  
  <p>With such solution, the export methods of the web service would return the dto's identified with GUIDs and the import methods would accept similar dto's - I assume the external system would be responsible for generating new GUIDs for new entities.</p>
  
  <p>What are the potential issues one might face with this approach?</p>
  
  <p>The technology stack for the system and web service is .NET / WCF / SOAP</p>