What is a Content Management Platform?
Jeff Eaton provides a pretty comprehensive post in Understanding 8: Where Drupal Is and Where it's Going, where he discusses these differences (at least in Drupal terms). 

Drupal as a Framework


  The foundation of that stack is the essential "web framework" code for
  Drupal. It's the portion of Drupal that provides essential services
  any web application would require. Rendering data into HTML and other
  formats, identifying and loading plugins, handling HTTP requests and
  responses, caching, database and storage access, and so on all live at
  this layer...


Drupal as a Platform (i.e CMS)


  Moving up in the stack, we find the "building blocks" layer that Catch
  referred to as the "Platform" in his blog post. This is where we begin
  to encounter Drupal-specific approaches to CMS and web building
  problems. The Entity system, users, nodes, taxonomy terms and
  vocabularies, actions, roles and permissions, FieldAPI, text formats,
  and our concept of "Blocks and regions" live here, and can be used to
  assemble features and functionality. Reusable user interface tools and
  UX components are also here: things like drag-and-drop tools, Drupal
  7's Overlay mechanism, and so on are all reusable tools used to craft
  usable interfaces.


These differences and more, are also covered in his DrupalCon London Presentation. Product, Framework, or Platform? What They Mean, And Why You Should Care

Essentially Drupal is both, a CMF and a CMS (and more) and why these discussions have come up recently in an effort for the community to define Drupal a bit more.