Tsundoku: The art of buying books and never reading them 8 years ago
I'm reading mostly on Kindle. So when I'm interested in a book, I don't buy it right away, I "send a free sample" to my Kindle. This way I at least save money. And the pile of samples in my Kindle serves as a to-read list. I only buy a book I fully read the sample and still want to read it.
One of the downsides of piling unread books for me is that later when I return to a book I feel like it's "old news". I have better chances to read a book when I first encounter it.