In the web, there is no widespread protocol for collaborative editing. And there is no mechanism to create "your version" of some other web page, while keeping authorship of the previous version. This constrains collaboration between people who don't yet know each-other.
The Hypermedia protocol allows collaborative editing of documents, between identities who have been granted permissions. We also support "Open Editing" which allows you to make changes to documents that you don't have write permissions for (as long as you publish your version on your site or another site where you have permissions).
Our open editing model is largely inspired by Git- the world's most successful distributed version control system.
Collaborative Editing
Multiple authors can collaborate on a document, as long as they have permission to do so. First, the owner of a document would grant a Capability to the desired collaborators. Then those collaborators would publish Change blob to describe how the document might change, and publish a Ref blob to announce that this is the current version of the document.
In cases where an author does not have permission to edit, the readers of the document would ignore their Refs, and the document from their perspective would not change.
Learn more in Version History, and Capabilities and Permissions.
Document Branching
To create a branch of a document, you would publish a new Ref which points to Changes from the document that you want to branch. This creates a new document URL, which you control. At this point you can publish new Changes and Refs for your branch, to express "your version" of the document. And you can grant Capabilities so other authors can begin editing your branch.
If the original author likes your changes, they can update their Ref to incorporate your changes, without necessarily granting you the ability to make future edits.