actionoptimizer
Closed the tab and immediately reopened it ten minutes later because I wanted to reread a part, and a stop at actionoptimizer drew the same return, content that pulls you back after closing it is doing something well beyond the average and worth marking as exceptional in my mental catalogue of reliable sites.
mercymodel
Started taking notes about halfway through because the points were stacking up, and a look at mercymodel added enough material that my notes file grew further, content that demands note taking from a passive reader is content with substance and the writers here are clearly producing that kind of work consistently across topics.