Now that I understand Dwight's idea, it makes a lot of sense.

I have never kept track of words that I look up, but I do have two other collections that are of a parallel sort. One is my quotations collection, in which I record things written by others that I think I might one day wish to use in some yet-to-be disclosed way. The other, the one for which I take a lot of teasing from my sweet bride, is my database (it used to be a notebook) in which I record all of the bibliographical data for each book which I have read since 1967.

Dwight's idea is no more lunatic than either of mine and sounds like it would produce some interesting data over time.