Over to Peter Norvig, Google’s Director of Research:
Course Builder is in fact a means of building dynamic online teaching materials that must be hosted on Google’s Cloud Platform-as-a-Service App Engine. So although the code itself is open source, it is closely linked with a paid service provided by the code’s authors. While there is a partial open source implementation of App Engine which might potentially allow institutions to host their own courses built using this software, it is not clear at the moment whether Course Builder is compatible with it. Certainly this thread in the Course Builder forums seems to imply that, for the moment at least, Google’s App Engine platform is a necessary component.
This provides an interesting example of open source code being used to leverage uptake of an associated service. App Engine’s charging model involves a free tier of resource usage below which users are not charged. Go above that level, and you will start getting bills.
Also of interest is the fact that Google are positively encouraging users to share the materials and courses they create using the software, with discussion groups dedicated to code and to content side by side. If this invitation to collaborate is accepted by the educational community, it could provide another impetus for institutions to take up App Engine use, as a key to using third party materials. Overall it’s a generous contribution to the corpus of educational software by Google, and one that may well help them drive custom to their services.