I think the example from "10,000 B.C.: The Geology of Morals" helps to clarify this.
The proof that there is isomorphism is that you can always get from one for on the organic stratum to another, however different they may be, by means of "folding" . . . There are irreducible axes, types, branches. There are resemblances between organs and analogies between forms. (46)Okay, so any two things can be connected somehow by "folding." We're getting somewhere now. And even though the second guy is trying to argue with the first guy, I think this helps to make more sense of rhizomes. The relationship between two things can be demonstrated and interpreted, even if that relationship is that there isn't really a relationship. The point is the connection between the two things can always be described somehow.
So let's talk about how this opens us to new ideas and thoughts. (First, let me make a disclaimer: this is going to over-simplify the concept of a rhizome and its potential use in my field.) Everything is connected in a complicated web of relationships. The strip of paper on my desk is connected with the tablet PC in my bag in several different way. By being aware of their rhizomic state, I instinctively begin to look for connections and see the greater One-ness of everything. I see how the actions of one thing affect all others, and now the pen sitting next to me has much more significance.
That's kind of an "I Heart Huckabees" soft-existentialist type philosophy, though, and not very useful to me as a tech writer. In relation to me as a writer and instructor, I am now aware I need to be aware of connections and relationships I had previously taken for granted or overlooked. Thesis statements relate to level of detail and also what sources are used; a student's thesis statement will also relate to their personal life and values as well. I need to be aware of these things to see how I can properly identify and interpret what a student is really trying to say and why so I can coach them properly. If I were writing an instruction manual, I'd need to be aware of how the different parts of instruction, pieces involved, etc. all related to each other in order to communicate them in the most effective, logical way possible.
Really, though, at the end of all this, I think D&G are really playing some sort of prank on intellectuals and philosophers in the same vein as Ern Malley.