I feel that what "adtech" refers to varies from person to person. It's becoming one of those charged terms where whatever online advertising techniques the use

I feel that what "adtech" refers to varies from person to person. It's becoming one of those charged terms where whatever online advertising techniques the user doesn't like are "adtech", while the techniques they don't mind aren't. If the infrastructure to select and distribute context-relevant ads is not "adtech", what is it?