Instant messaging or IM is a hybrid of e-mail. There are big differences however. IM is a synchronous form of CMC. As soon as you type a message and push enter, the message appears on the receiving person's screen. Depending upon what service you have you might be able set up your IM to let you know when a friend is connected. It also prompts you when someone begins a conversation through IM. You can choose to communicate with that person or block them.
"Instant messaging was created in July of 1996 by 4 young Israeli avid-computer users. These guys realized that millions of people were connecting to the Internet to use the World Wide Web, but these users were not interconnected. They created a technology which would enable Internet users to locate each other online on the Internet, and to create peer-to-peer communication channels easily. They called their technology ICQ, (I seek you). and released it in November of 1996."(Stewart,2001)
The educational implications are many. Students can have instant communication with anyone around the world. It is also becoming more and more common to have voice IM. So, students could actually speak to anyone around the world. Using this form of communication can have many benefits. Students could communicate with experts around the world on a subject they are studying. They could also communicate with peers and older student mentors.