This is an interesting interview from The Verge with the founder of Google Docs, Sam Schillace. He talks about how the project was born.
Talking about the auto-save functionality that Google Docs have, Sam says:
“The Save button is kind of funny. It’s obviously (to me) better to never have to think about saving, but we’re all conditioned to think about it, worry about it, etc. We’ve been trained to do work for the computer, which sucks. So, we really wanted to take that out, but it freaks people out when they “can’t save” their document. I think it’s funny — as though, if save were broken, your act of clicking on the screen would help the computer get that job done magically.”
The entire interview is kind of interesting. And hit the source link to read the complete interview.