Usage patterns
〈場所〉界隈the area around/in the vicinity of a place
There are many stylish cafes in the Shinjuku area.
〈事〉界隈the online scene/community centered on a shared interest
The topic is spreading within the voice actor fandom.
〈事〉界隈で話題になるto become a hot topic within a particular online community
This game has become a hot topic in the fishing community.