Stands for "Instant Message." Instant messaging, or "IMing," as frequent users call it, has become a popular way to communicate over the Internet. Two people with the same IM client software can type messages back in forth in a private online chat session. IM software allows users to build a list of friends, or "buddies" and displays what other users are online. After seeing who is online, the user can open up chat sessions with as many other people as he or she wants. While I find it difficult to focus on one conversation at a time, apparently some teenage girls that can keep more than ten conversations going at once.
Instant messaging can be a much more efficient way to communicate with others than sending multiple e-mails back and forth. For this reason, IMing has become a useful tool among friends and co-workers. Some people even find it more convenient to IM their friends than to talk on the phone, which I do not understand.