I found a web export of my old Delicious Library and it reminded me how fun it had been to see all my books in a beautiful and playful format. Delicious Library is a great app, but I'd stopped using it at some point for reasons I don't remember. I put the old exported web site out in a Google Cloud bucket for safe-keeping here: http://dellibrary.baty.net/
I thought it would be fun to see what had changed with Delicious Library since I last used it, so I downloaded the latest version. Of course when I launched the app my old library wasn't there. “No problem,” I thought, and went looking for a backup or export of the original library. It turns out that I don't have one.
How is it that after spending days and days entering books over several years, I don't have a backup copy of my library? This represents a complete failure of my “system”. Now I feel like I have to spend time, again, making sure that I have a way to archive and recover everything that means something to me, or might mean something to me in the future.
Keep backup copies of everything, and know where they are and how to find them.