timothy from the and-then-there-were-none dept.
extrarice writes: "See here
The "rent-a-book" concept is here. Pay a buck, and you're allowed to read for a cumulative total of 10 hours. After that, the text is inaccessible (unless you somehow access the content you purchased...)"
It is masked but always present.
I don't know who built to it.
It came before the first kernel.