What could Japanese Pokémon Crystal players do online?

The Japanese Crystal's Goldenrod City holds a building the West never saw: the Pokémon Communication Center, a larger replacement for the Pokémon Center that housed the Mobile System GB services, all of which launched on January 27, 2001.

Its Trade Corner, costing ¥10 (about 8 cents at the time) per use at the listed rate, let a player leave a Pokémon with a requested species and browse what others across Japan had left, trading asynchronously with strangers. It is the direct ancestor of the Global Trade System that Generation IV would make famous five years later. Ordinary trades and battles could also be arranged over the phone connection, paying only carrier fees.

Pokémon News, ¥100 (about $0.63) a month, compiled data from the saved games of players nationwide into a news service read at the News Machine in the Center, an early experiment in games reporting on their own communities. The Battle Tower could be challenged through the system for ¥10 (about 8 cents at the time), an Odd Egg could be claimed with an Egg Ticket, and Mobile Stadium, from February 8, 2001, let Crystal battles be uploaded into Pokémon Stadium Gold and Silver on the Nintendo 64.

Every one of these features was removed from the Western Crystal, whose Goldenrod Pokémon Center is an ordinary one and whose Battle Tower simply stands open. The two Crystals, Japanese and Western, are meaningfully different games, and the difference is a whole online world.