One of the major differences with traditional systems is that the name of the thing isn't the thing itself.
The thing itself, which is the perception of the thing that can have the user of Notion System, is the whole of the information available: names and relations with other concepts (notions).
In most cases one or more of the relationships define a context in which a name is, without ambiguity, related to the concept it stands for.
When communicating to each other a human perceives what the other said or showed through the glasses of his or hers own experience. We put the information we received in connection with the things we already know. So we do some interpretation. One of the factors of miscommunication is that the context we refer to isn't the same as context the other one refers to.
Most of the actual information retrieval systems are still word based. More and more these systems put the expressions in a reduced context (most often domains). If you have been trying to affect a particular expression to a domain, you will surely have encountered the fact that you don't know what domain(s) you should affect it to.
This is quite normal because the world we live in is really a complex one. Everything is, in some way or another, related to everything else. Sometimes the paths are short, sometimes they are extremely long. Domain specification, even with hierarchical levels, illustrates only very imperfectly how concepts are related.
This problem tends to be solved by Notion System. It will provide the context (all the information known about a concept, including its relationships) of a notion so the user will be able to have a clear idea about what the notion is really about.