Any information system should have two access points - search and browse. When users know exactly what they are looking for, they are going to use search. If you have enabled metadata search in your system, this search is going to be precise and will retrieve documents that users are looking for.
If users do not know what they are looking for, they are going to use browse to navigate to documents. Somewhere, some time during their browsing they may switch to search and then back to browsing.
In order to enable browsing or navigation in your system, you must create taxonomy and organize your documents according to this taxonomy.
But how do you apply the taxonomy that you created to your content management system (CMS)? Each CMS has a hierarchical structure. For example, SharePoint has the following structure: site collection --> site --> sub-site (optional) --> library --> folder, Vasont has collection group --> collection --> content type. And so each CMS has a hierarchical structure which could be adopted to your taxonomy.
Let's look at a specific example. Your taxonomy may look something like this: department --> unit --> content type --> subject --> date.
If we take SharePoint as the CMS you use, then: department = site collection; unit = site; content type = library; date = folder (for some content types) or subject = folder (for other content types).
In other words, each taxonomy unit is the same as a unit in the hierarchical structure of your CMS.
So, our example within CMS would look like this:
Engineering Department Site Collection --> Electrical Engineering Site --> Drawings Library --> Building Electrical Wiring Folder
Engineering Department Site Collection --> Electrical Engineering Site --> White Papers Library --> 2012 Folder
So, if somebody tells you that a CMS does not have a functionality to create taxonomy, ask them what is the hierarchical structure of this CMS and adopt this structure to your taxonomy.