Unlike email, IM detects the presence of a user on the Internet, and allows for consumers to use their keyboards to converse in real-time online, somewhat like using a TTY to talk over the phone.
Users can also set up conferences with several people online at the same time.
Right now though, users of one system often can't talk with those who use a different system. We anticipate innovations for wireless devices such as pagers and cell phones, which enable real-time communications to become easy and compelling. We are concerned that this sort of innovation won't happen if each provider uses a different protocol. I find it to be effective, and more importantly, functionally equivalent to what people with normal hearing experience over the telephone. I use it to talk with business associates on a daily basis.