Dear Father Steve,
As you are a multiple dictionary lookup man, your mode of operation would introduce an additonal challenge but my idea is fairly simple.
When I was given the 2 volume Shorter OED for my 60th birthday, I became intrigued with the idea of keeping track of the words I looked up, why I looked them up and how my understanding was enriched by the look up.
Like us all, I forget so much. So the first thrust was to have a marker within the dictionary so that I might go back to the word I had looked up and probably not retained. Then I found a second benefit, that my lookups actually were a documentation of some history: conversations with my son, discussions with my loved one, books I had read.
So given a vehicle I thought that the record of dictionary lookups might have some of the aspects of a journal but with the particular connection to the life around words and ideas and reading.
One other point of view is that such a record personalizes the dictionary itself. Dictionaries carry references, particularly the OED, -- how a word was used generally by the noteworthy authors. That book "The madman and the professor" on the OED, documents how references were gathered from readers all over England and then the startling things was that many of them came from this inmate for the criminally insane.
Each of us has his own particular claim to sanity and insanity and the way we use words and why is just one part of that.
Finally, dictionaries are basically databases. Technical novice that I am I wonder -- couldn't each person maintain a relational database which over time would show all the words that one had looked up and why , etc. Some relation would need to be built to an online dictionary and the recorded lookups. I have not in anyway thought out the technical implementation but I have the faith that a database technician could.
In the internet era, the possibility of gathering usages in the way it was originally done for the OED would be greatly enhanced.
Hope this clarifies. Thank you for your interest.
Dwight Eastman