Mognet

Mognet is a postal system run by Moogles. It first appears in Final Fantasy IX.

Final Fantasy IX
In Final Fantasy IX, the Mognet system is introduced by Kupo in a church steeple in Alexandria. However, since the Mognet system has been acting sporadic, Kupo requests the party to help him and other Moogles deliver mail to one another. He gives a letter for them to deliver to another Moogle named Monty.

Whenever the party talks to Moogles found throughout their journey, Mognet is provided as one of the menu options. Sometimes, by selecting it, a Moogle may request the party members to deliver a mail on their behalf, just like with Kupo. While infrequent, it is possible for the party to receive a letter from another character through Mognet. A prompt in the bottom-left corner of the screen notifies them whether they have mail or not. The party can carry up to three letters at a time. After visiting Mogmi and Moguta in Gizamaluke's Grotto, they can earn a Kupo Nut each time they successfully deliver a letter.

Later, if the party rides a Chocobo to the Mognet postal office, Mognet Central, it is revealed that the delivery system has been having mechanical problems because Artemicion, who is in charge of the Mognet system, decorated his coat with the oil used to power its machines. As a sidequest, The party can optionally help restore Mognet Central's functionality, but only once they have delivered every Moogle letter.

Final Fantasy III (3D remake)
In Final Fantasy III's 3D remake, Mognet is a part of several side quests in which the party must send mail to various characters. Players can also use Mognet to deliver mail to their friends via Nintendo Wi-Fi Connection.