It's the word "modality" that throws me. The word by itself is pretty vague -- "somehow related to a mode". The linked Wikipedia article is dense and confusing. You explain it as a way of modifying a statement. Then you say a publication is an "extended modality". That requires another mental stretch. How does the abstract idea of "a publication" connect to modifying a statement? One expects you to explain that in the following sentences, but you don't really. Instead you follow with the seemingly unrelated statement, "A researcher may wish to state a conclusion: “water boils at 100 degrees celsius”. Convention dictates that he should initially add various hedges to his conclusion: ..." So when writing a publication a researcher will customarily add hedges. What does that have to do with a publication being an "extended modality"? Is it really necessary to use such an obscure term? It seems like it shouldn't be this hard to understand what you're saying.
I definitely agree about the linked Wikipedia article on modality. Literary theory is probably not a good way to talk about modality with programmers, but the idea of modality isn't just about linguistics and literature, and isn't as obscure as you think.
A better starting point for programmers and computer scientists would have been modal logic, which uses the modal operators of necessity and possibility.
For example, classical logic uses propositions. I can say "P" in classical logic. In modal logic, I can say "P", "Necessarily P", and "Possibly P", where logical necessity and possibility are modalities. See http://en.wikipedia.org/wiki/Modal_logic -- it's a pretty good overview and it links the logical and epistemological senses of modality.
