Wonder Trade is a part of the Player Search System (or PSS for short) in which two people connect via wifi to trade Pokémon, each not knowing what the other has chosen to trade. The players are randomly found after the pokemon selected to be traded has been chosen, at which point, after another player has been found, the trade will commence.
Anyone who you trade with will be added to your "Acquaintances" list on your PSS database.
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