A couple of posts on Profiles in the DSTU-2 candidate from the guys at Furore:
- http://thefhirplace.com/2015/02/12/the-evolution-of-profile-to-conformance-package/
- http://thefhirplace.com/2015/02/13/fhir-profiles-and-implementation-guides/
These guys have been involved with – and supported – FHIR from the very beginning, are the maintainers of one of the FHIR test servers (Spark) and are also the authors of the reference profile editor (forge) so they know their stuff!