So I'm working on a spreadsheet and I email it to 10 people. I fix a formula, widen a column, and send another revision around. One more change, and ... maybe I'd better send it to only the 4 people who ever actually open it and give me any feedback, until it's done. You send an IM to one of them: "Did you get the updated file I emailed you?"
You've been there. You do a few more revs, and you rename the file, "Final 1", "Final 2", "Final 3". And finally you're done. You send one more email out to the group of 10, "Final 5.xls".
A week goes by. You start getting email from some of those 10 people. "Do I have the latest version?" or "Can you send me that spread sheet you're working on?"
This is how most people share documents and work on them as a group. The above scenario generates 54 (fifty-four) copies of the spreadsheet (including the 5 final and one draft revisions I kept on my machine), and distributes it over at least 11 computers.
No wonder we need 200GB disk drives.
There is a better way. It's called centralized file sharing. The problem is, nobody uses it, because it's too much of a hassle, another password to remember, somebody else has to set it up, maintain it, back it up, etc. It just doesn't really work, does it?
"I sent you the final version yesterday, Final 6.xls; did you get it?"