What is it?
Instant messaging covers everything from spam pop-ups to global corporate conferencing. Best known as a kind of SMS texting for PC users, instant messaging is an IP-based technology that is being extended to include mobile devices such as phones and other media such as voice and graphics.
There are consumer instant messaging services run by third parties, which are generally open to all and entirely insecure. There are also private, secure corporate instant messaging applications, which can be used internally and over the internet.
The technology is still very immature. There are no common standards and no guarantees that instant messaging platforms from one supplier will be able to communicate with another. For example, AOL's instant messaging is not compatible with ICQ, which AOL owns.
Where did it originate?
In 1996 Israeli company Mirabilis devised the first instant messaging product, ICQ ("I seek you"). It was later acquired by AOL.
What is it for?
Spam, chat, alerts, polling and conferencing. Polling can be used as a way of getting rapid feedback from a scattered group of people when a decision needs to be made quickly.
Permanent, private conference rooms can be set up for people collaborating on projects. Just like news groups, the conference sessions can be moderated and the transactions can be archived.
Instant messaging can also be used for file transfer to enable users to share documents or for subscription-based news and information services. It can also be linked to calender and diary applications to provide real-time reminders.
What makes it special?
Instant messaging enables users to communicate almost as quickly as over the phone but without the costs, and provides an auditable, archived trail of messages without the time-lag of e-mail.
You can keep track of which of your colleagues are online using "presence" information. Although this means that people can potentially reach you whenever you are online, some instant messaging products, such as Sun's, allow users to make themselves "invisible".
How difficult is it to master?
Key skills include Java and C#, or a background in messaging server administration. Instant messaging also provides an introduction to technologies such as .net, C# and Shared Source CLI.
Where is it used?
Alongside consumer and internal corporate applications, there has been a growth in the use of instant messaging by brokers and others in financial services. However, there are potential regulatory problems and some organisations have banned it.
What systems does it run on?
Windows, Linux and Java platforms. Instant messaging platform suppliers include Microsoft, IBM/Lotus, Sun and open-source instant messaging supplier Jabber.
Not many people know that...
Microsoft calls instant messaging pop-ups "toasts". When two or more appear, it is a toast collision.
What is coming up?
The Internet Engineering Task Force has two working groups tackling two emerging common standards: XMPP/Jabber and Simple (SIP for Instant Messaging and Presence Leveraging Extensions).