In real life, we usually don't think about namespaces, because most names clearly indicate what kind of things we are talking about. "yellow" is a color, "birch" is a tree. We don't have to qualify "yellow" as the name of a color, because we know it implicitly.
When programming, however, namespaces are more important: When talking of attributes, many different things can have the "id-number 45268". If all things exist in the same namespace, we assume that 45268 uniquely identifies something. If people, projects, and companies all exist in their own namespace, we have to qualifiy the id-number. Is it the id-number of a person, a project, a company?
Although the term "NameSpace" is in common use within the software jargon, I think it is doubtful whether it is chosen well. The "space" part is badly founded, because typically space concepts like distance, direction or neighbourhood have no meaning. To me NameSpace means something where vectors exist which be combined to get to points in space. A wiki is to me a semantic namespace. Certain words have the quality of semantic orthogonal vectors. The word-vectors "Wiki" and "Community" and "Shallow" may be combined to get at the semantic points "WikiCommunity" or "ShallowWiki" that have some special, real meaning (at least for us). It makes sense to analyze the words that are used in building wiki page names. They tell us a lot. Wiki clones like MoinMoin or ProWiki support a word index (e. g. DseWiki:action=wordindex&count=5). -- HelmutLeitner