Unfairly a part of me thinks this is the work of a troubled mind. On the other hand, I am having difficulty remembering what books I read back in the 1970s and if I had been this diligent then I wouldn't be having this problem. He presaged Librarything by decades.
Interestingly, 52 people have tagged this web page in delicious. I think most are in awe.
A new take on personal cataloging of books etc is gurulib which I have yet to test out but it has a similar purpose to Librarything. We all need a little competition. This site is free for the moment although Librarything was hardly expensive.