What online trading feature did Pokémon Diamond and Pearl introduce?

Pokémon Diamond and Pearl introduced the Global Trade Station, commonly abbreviated as GTS.

The feature used the Nintendo Wi-Fi Connection to let players offer a Pokémon and request another species from players around the world. A trade could remain posted while the player was offline, allowing another user to complete it later.

Diamond and Pearl were released for Nintendo DS and formed the fourth generation of the main Pokémon series. Their online features also supported battles and communication, making the games a major step beyond the local cable and wireless trading systems of earlier generations.

The GTS is distinct from Wonder Trade, which appeared later and assigns a random traded Pokémon. Pokémon Bank was a separate storage service, not the original global trading system introduced by Diamond and Pearl.