Chapter 17: "Rethinking Files and Save" of About Face covers this. Alan Cooper is well-known as a usability expert and his writings are influential. His argument is essentially that when we force the user to think about the implementation, we get ourselves into trouble. Here's a brief excerpt:

In the world of digital technology, the place where implementation-model thinking most strikingly rears its ugly head is the management of files and the concept of "save." If you have ever tried to teach your mother how to use a computer, you will know that difficult doesn't really do the problem justice. Things start out all right: You start up the word processor and type a couple sentences. She's with you all the way -- it's like writing on paper. But when you click the Close button, up pops a dialog box asking "Do you want to save changes?" You and Mom hit a wall together. She looks at you and asks, "What does this mean? Is everything okay?" This problem is caused by software that forces people to think like computers by unnecessarily making them confront the internal mechanisms of data storage. This isn't just a problem for your mother; even sophisticated computer users can easily become confused or make mistakes. People spend thousands of dollars on hard- ware and software just to confront impertinent questions like "Do you really want me to save this document that you've been working on all afternoon?" and must remember to use to the Save As... command when what they really want to do is work on a copy of the document.

It's worth thinking about ways to simplify or eliminate the "save" metaphor.

Here on Stack Overflow we can "Post an Answer" or "Add Comment" or "Ask your Question" for example. Each time we really are "saving" to the database, but the metaphor is slightly different each time. Posting, adding, asking. I think of software like iTunes which I believe does not have the concept of "saving to disk" for the music. You simply add music to it and it's saved. Depending on the type of tasks your software carries out, there may be different metaphors which are more apt than save.

I should mention that I've not really answered your question, I myself have used the floppy icon, or a big button that just says "Save" on it in my web applications. For the time being we're stuck with it for many cases, but it gets more and more ridiculous as floppy drives die out. But then, we also say we "dial" phones, when dial-interface phones have not been in popular use for decades.