I looked into it at one point, as I was disgusted by the unskippable advertisements when paying for an ad-free tier on one of the myriad streaming platforms. Apparently, they distinguish between "advertisements" for a product or service and "promotions" for themselves. I get why that would be a reasonable internal distinction, as the former would require sign-off from the business paying for the advertisement, while the latter would only need internal approval, but it's a pointless distinction after that.