I've admitted elsewhere that I'm a Luddite. I use Goodreads to track everything. But I carry a pen and small spiral shirtpocket notepad around with me most of the time. When I read, hear or see a title I might want to add, I write it down and add it to my "to-read" list on Goodreads. That list contains both owned and desired purchases. I can print it out and take a copy with me when I head for my favorite used bookstore. A spiral notepad and pen are slightly cheaper and far more reliable than a smartphone.
