Coming up with a new model for social media and also dictating what features are good and bad for users is going make user adoption a tough challenge.
An "AppView" is the API server that most clients connect to that aggregates data from the network and serves it in a more useful way. mu.social still uses bluesky's AppView (api.bsky.app).
The name is confusing. I thought clients were appviews myself for a while.