Imagine, for example, that you're talking to a friend or colleague on the
phone, and you decide that the answer to the problem you've been discussing
is for the two to you to sit down and draft a letter or document. The wonders
of modern technology means, of course, that there's no need to wait until you
can get together in the same room, in front of the same computer screen. All
you need is for each of you to head to the nearest computer and log into this
special website. Think of a title for your document, type it in, and both
surf to the same web address. Within seconds, you're both working on the same
document in real time. As you type, your words and edits are instantly
reflected on the other person's screen. Separate colours are automatically
added to make it clear who typed what. And if there's more than 2 of you,
additional people can even join in too.
http://www.techsupportalert.com/content/instant-collaborative-document-creation.htm