What is Twitter, why should I use it in my daily business?

Since more than a year I'm an user of Twitter. Sometimes I got questions from people why I uses Twitter. This weekend, I  got this question from the 90 years old grandma of my wife. She does not have a computer but has read some articles in the newspaper about Twitter. See some examples of twitter articles in the dutch newspaper NRC Handelsblad.

The first reaction of people who see Twitter for the first time is:
Why should I tell what I'm doing?
Of course this is a valid question. Please read next post of Computerworld: Twitter: The how to get started guide for businesspeople to get more understanding of the use of Twitter.

Happy Twittering