Now I have checked out the open education projects suggested.
Warning - Each of them seems to contain a lot of information, modules, functions and so on. Any impressions that I mention here are formed after this first short glimpse of these sites and are not really to be trusted!!
The projects can be split into two groups. The MIT and OU projects seem to mostly offer ready made educational materials. I felt there was something of a take-it-or-leave-it attitude but the OU does offer a Getting Started section with a very user-friendly area to help you as a student use the materials offered.
Rice Connexions, Le Mill and Wikiversity are all communities where you can both use the material on offer and also contribute to the material – in fact you are strongly encouraged to get started with your contributions! Rice Connexions definitely wins the prize for the easiest site to search for materials! I had problems finding my way around Le Mill, partly because a lot of titles are not in English so you have to open an object to see what it is about. Of course, this disadvantage could well be seen as an advantage if Estonian is your first language.
As I browsed I found that these different projects can be linked together. The Le Mill Atmospheric Processes unit used a module from the OU’s OpenLearn site as reference material.
Another way to divide these projects would be by language. If you need materials in English there is something for you in all of these projects but if you are looking for materials in other languages then the different sites have hugely varying amounts.
Terminology – modules, learning resources, media pieces, collections – each project uses its own terms. In practice I suppose most users stick with one or two projects and quickly learn the associated terminology.
These five projects contain a huge amount of educational material and there are many other projects, including CFL:s own Course hub. Perhaps the next stage is to find a way to search the Internet for OER, or perhaps a specialised search engine already exists. If you know of one please get in touch!
PS I found the photo illustrating this entry by searching for "open educational resource" in Flickr. There were plenty of images to choose from and most of them were free to use under the CC licence!