On the other hand, surprisingly few "ad-free" service tiers turn out to actually be ad-free, which tends to undermine the whole concept. It's extremely common to get various kinds of "special" promotions that don't go through the standard ad platform. Sites have been known to forget the premium option when A/B testing changes to ad placements. Multiple streaming services have ads on some shows even on their top "ad-free" tier (I think because the ad buy was with the original studio/network and is written into the show's distribution contract). Several marketing gurus have figured out ways to game social media networks to make "non-advertising" posts featuring their brands go viral (see e.g. the fad of "weird brand Twitter").