Corporate instant messaging client for use in a business LAN with a set of enhanced features including standard software compatibility such as WinPopup and Messenger Service (net send), group messaging, automatic answering machine, message history, file transfer. Real-time communications can be organized with Peer-to-Peer or Client/Server instant messaging architecture. Using a central server users get powerful options to organize an effective communication system with news notification, centralized user grouping, offline message storing and automatic delivery, creation and management of public user information, receiving account list with user presence status.