As ideas occur real-time, traditionally (pre computer age) people would typically record thoughts/ideas/research in the order they occurred, and then come back and pull out similar veins of thought as they rewrote or reorganized their notes. Some have used separate notebooks or sections of a notebook for separate topics.
Today, I am sure there are different methods emerging that take advantage of modern technology and other organizational schemes to categorize things. Stack Exchange uses tags because they are a handy way of grouping similar threads of information which can easily be grouped and searched by keyword/tag.
The question I would like to ask is, if there are any methods of "advanced tagging" which could be utilized within a simple text editor or word processor?
To use a practical example, I have typed and/or gathered incomplete thoughts into a word processor (information gathering) that are not in any particular order, and it's likely that several of those thoughts could fit into multiple sections. If there are 100 pages of information, it would be inefficient to cutting and paste thoughts one by one into what seems to be the most relevant section, as the organizational schema could morph as information is processed/incorporated, and a single statement or thought could fit into several categories. I think what I am really asking is if there is a particular organizational approach I can take to organizing a tagging system or recording where a particular thought might fit in.
I am looking for something content agnostic if possible, and am not looking to built a complex relational database... just a system that could be applied to my "information gathering document".
Help to refine this question (via edits or commentary), without changing the intent, would be appreciated.