It has taken me all this time to work out a useful function (for me) for these two classification criteria. This has been an important result of the blog curation process. Simply put, categories are very wide groupings similar to chapters in a book. They tell something of the area of interest but not its content. Tags can be likened to the contents section of a book. It is there where one searches for a particular term used, name, place, process, etc. Tags like content will list all the relevant words that I might find useful in the future if I wish to search for something. For example, if I want to look up a particular artist I have written about and cannot remember where to find it, I type the name and all the posts that contain that name will appear. There is an even more powerful function, and that is, if I want to refine the search because too many posts appear in the search, I can type two or more keywords, or tags. This will narrow the search results to only those posts that contain all those words.
So far I have 1092 tags. This may seem a large number and no doubt will continue to increase. However, the number is of no consequence. It is only important if one wants the tag cloud plugin to say something useful. But the cloud plugins only deal with a small and limited number of tags. For this reason I have decided to remove the tag cloud widget from the side bar. As for categories, I have been able to cull them to be less confusing.