The inhabitants simply called it The Village.
In 1962, The Network discovered the Village constantly popping up across the US. They helped connect it to the rest of the world, building up its infrastructure and adding a wireless connection to the telephone system that would later be the inspiration for cell phones. They made the place their primary base of operations, and the Village renamed itself Net.town in their honor.
The Network's presence and the advanced technology they brought to it made Net.town grow like crazy. As it grew, it was renamed to Net.city, then Net.ropolis. The Network broke up in 1985, but in the '90s, the Saviors of the Net made the city their home – until The Killfile went up. After these events, city leaders decided to make the homage to the Network less explicit, re-renaming the city as just Netropolis.
After the Killfile fell, the LNHQ arose, and the LNH came together, making Netropolis their home!
Netropolis is not simply a city; it is the idea of a city, manifesting as one. It's a Brigadoon-like location, except that instead of vanishing completely it simply moves. A bit of unreality that attaches itself to the world wherever seems to fit best at the time, driven by forces no one can quite fathom or predict. Sometimes, the transition is abrupt; other times the inhabitants have warning enough to make sure they're either in or out of town as per their preference.
Rather than moving physically, Netropolis attaches itself to the underlying noetic substrate of reality. All of the mundane practical matters, such as road/train connections, suburbs, and so forth are shuffled into the right spots when the city moves. Prior suburbs go back to being small independent cities with histories that realign to no longer include a sprawling neighbor, or they simply shift their allegiance (i.e. if Netropolis spent time an hour away from Cleveland, its suburbs would go back to being Cleveland's, the towns moving into the empty space so as to be closer to the other city). If Netropolis grows significantly during a period of stability, suburbs might become fully entangled in its noetic field and start moving with it every time.