Documents that contain information on, or a guide to, a specific process, function or feature of a product, without being a manual or install guide.
Documents that give a brief overview of a product, and a general appraisal of that product's capabilities. May contain a few brief technical details.
Documents that contain extensive technical information and/or wiring diagrams that will allow you to wire, configure and use the product.
Documents that constitute a full manual for a particular product. These will usually be the largest and most comprehensive documents.
Any document that either does not fall into one of the other four catagories, or is outdated and in the process of being revised.