I remember the rise of tagging “folksonomies” and the rush to add them to blogging software at the time (2005ish, per the original article). Because of how they were implemented there was always a tension between organising content through categories vs tags, which meant some blogs didn’t use them, while others went “all in.”
For myself, I’ve found myself drifting away from using either. I used to categorise posts into a particular theme, and then tag with more fine-grained keywords. Back when your “content” and “niche” “mattered”. Now I almost never bother explicitly setting either; I blog for myself, so I don’t feel I necessarily need to define everything into a taxonomy that helps other people make sense of things. Maybe I should put more effort into this, for the day my memory starts failing me?