And public libraries. For example, if you live in the Houston area, the Harris County Public Library has several licenses to Safari. (hcpl.net)
I sure wish O'Reilly had an affiliate program. I would collect the name of every public library system that offered Safari, SEO the name of O'Reilly books, and direct people to their local library's license of Safari with a helpful affiliate ad to buy their own copy.
Note: the public library version of Safari is not quite the same as a personal (or corporate?) license, but it is very similar.