The function that makes a Mac so useful is its ability to copy. The most common things people do on a Mac are to 1) type and then 2) copy what they just wrote for different uses. Want a new document? Just select your favourite similar document, copy and paste all your favourite bits, add a few sentences here and there and voila, you have a new document suited to your purpose. Want to share? E-mail a copy. Want to broadcast? Post a copy on the internet. Want to get into trouble? Sell a copy of something that belongs to someone else. Copying - it's what computers do.

Nonetheless, the Mac's ability to copy documents, art, music, photos, movies or anything else digital is what makes it such an incredible time-saver and useful production tool. All this became clear to me one day when I wrote a column that, in one hour, caused 400 people from all over the world to send me e-mails asking for clarification on different points within it. The queries were essentially made up of seven questions. Some needed answers one and three; others needed answers five, two and seven. Four hundred e-mails, requiring 400 different responses using various combinations of answers and I responded to them all in less than three hours.

The secret, of course, was copying. I used a simple clipboard management tool called CopyPaste, which allows you to select something and copy it into a little segmented database that hovers over your desktop.