Mobile IM and Presence

IM clients are also developed for mobile devices.

SMS's (short messages) may be considered a subset of Instant Messaging. Generally, an SMS may be stored by the carrier when the mobile device is not on. Additionally, the SMS will be stored on the device once it gets there and thus, not require the user to be actively interfacing with their phone.

Alternatively, IM clients will use the device's data service and generally require the recipient to have their device on. Because of this, a protocol has been developed to monitor an individual's Presence. For example, your IM contacts may determine whether the your phone is on or off, if you are in a call, if you are available, unavailable, or in a meeting. Additionally, they may be able to determine your location, your device's capabilities, even your current mood and a list of hobbies if you choose.

Instant Messaging

Instant Messaging is a technology that allows two or more entities to communicate "privately" over the internet in real time. Typically, an individual will install a client application on their computer that will handle the communication with other individuals on the same network. The concept of Instant Messaging has been around since the 1970's particularly on multi-user operating systems. Applications such as AIM (AOL Instant Messaging) with easy to use graphical interfaces helped boost the popularity of instant messaging over the internet in the late 1990's. Unfortunately, many companies have created messaging applications each of which communicate on a proprietary protocol. Thus, the different messaging systems do not allow you to communicate amongst one another. As a result, clients, such as Pidgin, have been developed that allow you to maintain all your IM conversations in a single interface. These clients are known as Multi-protocol Instant Messaging Clients. Even though they are able to communicate over the different networks, you must still have a separate account for each of the networks to which you connect. Meebo.com is the first example of a web based IM client that I have seen.