A free-form discussion without threads is a real mess, because when you read an individual contribution you can't tell what it was in response to. Introducing threading helps by preserving the context from contribution to contribution. Viewing a free-form discussion as a series of threads is an improvement, and the concept has been around for a long time.
By curious twist, Thread has attained a negative connotation on Wiki because of its association with multiple part discussion and the ills that sometimes accompany it, harkening back to the original free-form chaos. Thread (the term) has become an abstract handle on that original problem. So we have a language paradox here, where the solution has become the shorthand for the problem.
On DissertationOverDiscourse you can read about authoring style preferences, and learn that the appearance of single authorship ("DocumentMode"), even if we know it's just an appearance, has desirable qualities when it comes to understanding the material later. This style exploits a single thread. The local antithesis of dissertation ("ThreadMode") has multiple speakers, but from a pure Thread perspective it is the same -- still a single Thread.
The lesson is this: As long as context is adequately preserved, written material is readable and accessable. The choice of solilloquy over dialog has to be made in a different context, the higher one of the author's (or authors') intent. This perspective is offered in the spirit of unification, as it's often valuable to see both likenesses and differences in the things among which we choose.
See also: