The internet is vast, but it brings like minds together. At its best, it serves to unite kinky freaks, dissidents of oppressive regimes and sufferers of obscure diseases. At the same time, this tendency can serve the cruel or misinformed — giving shared language to Nazis and incels and other bleak dopes who were once kept mercifully isolated from one another. This feature of the internet is, at best, value-neutral; in any case, A.S.M.R. tests its limits. The YouTube subculture is bonded not by belief but rather by an ineffable sensation — perhaps the first time the internet has revealed the existence of a new feeling.