there's that whole critical mass thing. groups get established, and once there's a migration of outsiders it feels strange. people do this predictably over and over again.
what most of all these tools lack is a way to creatively filter without being annoying to the end user. at the same time, filtering has its own set of issues, notably you miss out, but at the same time i know assuredly i don't need anime crap showing up in my timelines, either. its a waste of spirit and my focus.