Who did Hermes deliver messages to?

Hermes was Zeus' son and his messenger, therefore the answer is he delivered messages to anyone Zeus instructed him to. At least one of these messages is referred to in the Iliad by Homer, where Zeus instructs Hermes to Guide King Priam of Troy To Achilles so that Achilles might grant Priam the right to give his son an honourable funeral. You can read about the many other messages Hermes carried in "Hermes the Olympian", available on Amazon.