Abstract: A server according to an embodiment includes a processor configured to receive a friend add request for a target account from a user terminal accessed with a user account; based on one of the user account and the target account being a protected account, transmit an approval request for the friend add request to a protector account connected to the protected account; and based on receiving a reply to the approval request from the protector terminal, add the target account to a friend list of the user account.

Abstract: A method for a first user terminal to use a messenger service of a group chat room is proposed. The method may include receiving, from a server, invitation information associated with a second user's inviting a first user to the group chat room, and displaying chat room information on the group chat room. The method may also include in response to the second user not being registered as a friend of the first user in the messenger service, displaying information on the second user and an interface for deciding whether to participate in the group chat room. The method may further include acquiring an interaction regarding a decision to participate in the group chat room through the interface, and displaying a message created in the group chat room.