Welcome to DiscDAG

It has some good aspects as the ability to branch allow to focus on some specific details more easily.

This particular solution seems to be lacking some mechanism to merge the discussion back together so that the tree doesn't branch out ad infinitum.

It also doesn't solve the problem of collaborative list building easily.

It's also simplifying the problem as it is not a asynchronous system but rather a standard single point of truth database.

The way I see all these collaborative tools is that they are trying to make up for their users lack of basic algorithmic knowledge. They are constraining the users into a specific point of view. But this is usually not enough because the user will want to do something which isn't done easily in this framework and new absurd phenomenons similar to top posting will emerge.

Database tools and basic algorithmic structures have been known for a long time now. The usual structures needed are lists, queues, sets, graphs, tags, custom structs. Standard database tools can do the collaborative part easily, you just need a good front-end to make them available to your users for when he needs them.

The alternative if you can't teach your user, is to have a nlp AI construct the database automatically. That's what there is in tools like gmail to automatically add to your agenda your flight reservations for example.

This project is called DiscDAG, and the description says you can reply to multiple threads all at once. Too bad the example image only shows branching and not merging. It hides the key differentiator of the system.

If you only happen to allow branching but not merging, then the result can be represented in a tree. Indeed, this is how Hacker News, Reddit, Slashdot, and mailing lists visually present their threaded discussions.

Also note that email has a header named "References" which can point to multiple email message IDs, so there is some existing infrastructure that can express a DAG. Too bad no email clients use it this way; every client I've seen will visually attach each email message to zero or one parent.