As many features w3clan has, some of which mentioned here :- https://news.ycombinator.com/item?id=12341180 also has One very important feature and that is "Multi Author" option.

Yes, w3clan has option to add as many author as one want for his/her course or tutorial or documentation. So, if your course or tutorial or documentation needs multi-author option, you can do that too with w3clan.