Do you think there might be a problem with leaning on a book that is nearly 20 years old when you are talking about communication in the modern workplace?
If someone left a hand-written note on my desk I would today put it in the same category as ‘venomous passive aggressive notes on the fridge’. It seems like possibly the least effective way to get someone to do something.
There might be a problem in taking it too literally, but I think the underlying concept is very current, and maybe even more important than when the book was written: as much as possible, favor keeping a written trace and avoid disruptions to others.
To the written note: I think that really depends on workplace culture and communication content. I see it as e-mail for printed documents. For instance, in my workplace, it is quite common to exchange printouts of scientific articles that way, with a post it "you might find this interesting".
If someone left a hand-written note on my desk I would today put it in the same category as ‘venomous passive aggressive notes on the fridge’. It seems like possibly the least effective way to get someone to do something.