Game system and game providing method using the system

A game system comprising:

• a game server configured for providing an online game to a set of participating users;
• an external server configured for providing a social network service to a general public, the external server not connected to the game server;
• a recruiting user terminal configured for creating a party of the online game, transmitting the generated party to the game server, creating a party member recruitment announcement comprising information on a participation condition of the party, and transmitting the party member recruitment announcement to the external server;
• and
• at least one participating user terminal of a potential participating user configured for receiving the party member recruitment announcement from the external server and transmitting user game information of the potential participating user for participating in the party to the game server in response to the received party member recruitment announcement,
• wherein the game server is configured to receive the user game information of the potential participating user, determine whether the user game information of the potential participating user satisfies the participation condition, and transmit a participating admission message to the participating user terminal if the user game information of the potential participating user satisfies the participation condition.