Lucky I got in my last edit to an old thread when I did. I had made an index of sorts on my 92-page project thread that was started in 2009.
The index became completely useless with the forum update when the default number of posts per page changed, so I was able to make the index a little more useful with my edit of 2/17/15.
This recent change doesn't make sense to me despite what you said about editing out material. I was always careful with my edits not to change anything that would change the flow of the discussion, only to correct or increase accuracy, so as far as I'm concerned a valuable and useful tool has been eliminated. Besides that, older threads are much more difficult to find by searching if no tags were used, so the ability to add tags is also gone.
But thanks for your answer.