What is driving the eBooks boom?

Via Yves Smith, here is one hypothesis:

What's popular on Fictionwise? Well, once again it seems like
porn is blazing a path to a new media format. Of the top 10 bestsellers under the "Multiformat" category, nine are tagged "erotica" amd the last is "dark fantasy"…People who read erotic romance and 'bodice rippers' love
ebooks because of the privacy they offer, both during purchase and when
reading.

By the way, Andrew Sullivan asks how one is to post 250 times a week and read Ulysses.  The answer is simple: one page at a time. 

One advantage of Kindle is that it provides a new tool for mental accounting.  Call me irrational but formerly I could not read more than seven or eight books at a time without abandoning some of them midway.  Kindle (like Netflix, I might add) gives me a new queue and allows me to have more "hanging," partially unread books at any point in time, yet without disrupting my mental equilibrium.  I'm rereading Moby Dick, one chapter at a time, on plane trips, and next in line are Middlemarch and…Ulysses.