Open educational resources are much more than simply free resources.  In addition, open resources give students and teachers the following five rights:

  1. Retain – the right to make, own, and control copies of the content (e.g., download, duplicate, store, and manage)
  2. Reuse – the right to use the content in a wide range of ways (e.g., in a class, in a study group, on a website, in a video)
  3. Revise – the right to adapt, adjust, modify, or alter the content itself (e.g., translate the content into another language)
  4. Remix – the right to combine the original or revised content with other material to create something new (e.g., incorporate the content into a mashup)
  5. Redistribute – the right to share copies of the original content, your revisions, or your remixes with others (e.g., give a copy of the content to a friend)

By contrast, most commercial digital resources allow students and teachers to use the resources during the term of the course after which access disappears, just as rental textbooks must be returned.

Source: David Wiley http://www.opencontent.org/definition/