The ones I've seen could be downloaded as ordinary .PDFs if you select that option in the menu.

I've contributed heavily to IA in the past and would never stick up for traditional publishing in a fight like this one. But turning themselves into a modern-day Pirate Bay was a suicidal tactic on their part. I can only hope they're playing some kind of long game that outsiders can't yet appreciate.

Maybe even jpeg2000 in some cases. Also long render times on computers; impossible to read on e-readers.