WIM, or Wireless Instant Messaging is quite a bit different than SMS and here’s how and why.

Short Message Service was first introduced about 1996 or 7. It was a GSM feature and didn’t get much traction in North America until only recently. It is widely used in Europe and Asia. I had to learn how to use SMS by a Swedish friend at an event in the UK.

SMS is a store and forward message. Wireless operators deliver it when they can, which often means nearly immediately. There are several scenarios that make SMS really silly. My boss is a subscriber of Sprint-Nextel. He has subscribed to AOL Instant Messenger’s SMS gateway service that lets PC users send SMS messages. Unfortunately, since we are a Canadian company (check out SIPquest), he spends a lot of time there, out of the reach of Sprint’s SMS service.

So, when he lands in Chicago and turns on his cell phone, it buzzes for about five minutes as all the SMS messages of the past week are delivered. Each of which is completely useless, since most started as IMs and not SMS.

Instant Messaging is derived from Presence services. If your computer is on, you’re ready to accept an IM. However, if you’re logged off, or the computer is off, you’re not able to receive. Instant Messages are sent directly between subscribers and not to a central server for transport, as in SMS and email.

Although this may seem subtle in practice, consider the scenario of sending an email to ask if I can call you now. Sounds pretty absurd, but that’s got to be the most popular IM outcome. The most popular message is “hi.” Followed by “Are you there?” and “Can I call you?”

Of course these include their IM shortcuts: “R U there?” or “U There?”

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