There are several possibilities to do so. However, there seems to be a lack of a single resource being really strongly used. I just came to this question because I was looking for a single service similar to the arXiv, but for teaching materials.
Wikiversity is a Wikimedia Foundation project devoted to learning resources, learning projects, and research for use in all levels, types, and styles of education from pre-school to university, including professional training and informal learning. We invite teachers, students, and researchers to join us in creating open educational resources and collaborative learning communities.
Just like Wikiversity and Wikipedia, this is a subproject of the Wikimedia Foundation.
Wikibooks is a Wikimedia project for collaboratively writing open-content textbooks that anyone, including you, can edit right now by clicking on the edit link that appears near the top of each Wikibooks page. Wikibooks has two sub-projects; Wikijunior which is aimed at children and the Cookbook which is our collection of recipes and culinary topics. Contributors maintain the property rights to their contributions, while the Creative Commons Attribution-ShareAlike License and the GNU Free Documentation License makes sure that the submitted version and its derivative works will always remain freely distributable and reproducible.
You can put your material on GitHub. I did so with a book I wrote about an introduction in Geometry and Topology (see MartinThoma/LaTeX-examples/tree/master/documents/GeoTopo). All source files as well as the compiled PDF are there for download. You can use the "Issues" to give others the possibility to give you feedback / note what you want to change. Forks make it possible that others fix typos directly by themselfes, just making a pull request instead of writing an e-mail.
People seem to upload lecture notes to the arXiv, too:
- arXiv has a good reputation in mathematics and computer science (I guess in physics, too). However, it seems not to be usable for non-physics related chemistry. However, there might be plans to extend it for chemistry (see Tweet). I would definitely use it for publishing lecture notes. arXiv guarantees that the content will be available, makes it citable and gives a relatively central point to look for new content in the field
- GitHub is great for collaboration with arbitrary structures / content. However, your collaborators need to know how to use git and the lack of structure might also be a disadvantage.
- Wikiversity and Wikibooks ... well. They exist for quite a while and some content seems to be pretty good, but I've never used it myself. To me, it seems like a negative compromise between a website, a Wiki-system and slides. I just think it doesn't look good. On the positive side, one has to say that using it is really easy and the materials you create are available for everybody. Especially for images (see my images for mathematics, for example) it is very nice if people add their content on Wikipedia Commons.
What I would like
A web service where people could create accounts, upload arbitrary stuff (especially PDFs, probably also LaTeX which gets automatically compiled, images).
- There should be a possibility to describe the content, tag it.
- With the description and the tags, it should be possible to search for it.
- People should be able to make comments
- There should be a StackExchange like privilege / reward system to prevent bad content / comments.
- People should have the possibility to make them identifiable (e.g. post a link to their profile on their university website which gets automatically checked or receiving a code to an .edu e-mail address).
I would like to discuss ideas about such a web service. As this seems to be the wrong place for such a discussion, I've created a GitHub repository and an Issue: What do we want? #1