A programme, usually downloadable for free, that allows people to chat in real-time. Many have integrated features such as file sending, two player games, pictures and drawing boards. They are basically an evolution of electronic mail that allows people to get closer to each other. The most popular IM programmes are aim, msn messanger, yahoo IM and icq
2) To use 1) to contact another user of IM's.
3) Mis-spelling of I'm.