I have worked on sites that do this (sorry) Filtering spam from engaged traffic is a big one. News sites tend to do it in the vein of TikTok: users can quickly

I have worked on sites that do this (sorry) Filtering spam from engaged traffic is a big one. News sites tend to do it in the vein of TikTok: users can quickly scroll to the next post if bored, instead of leaving. Some e-commerce sites do it to product descriptions and their ilk for the modern equivalent of keyword stuffing.