But my point isn't who-invented-it, it's that it's very easy to implement this in your own buttons without using Bootstrap. I still use my own implementation, despite suggesting it to them. Just create some data attributes (I have data-default-message, data-inflight-message, and data-success-message) and change your buttons appropriately. I have a standard function that I call on my forms that handles that for me, which I've gisted here: https://gist.github.com/pamelafox/5714109 You could do that in a more elegant way than that bit of code. :-)

I prefer the changing-message approach to the showing-the-indicator approach because the verb stays, and you remember what it was that you were doing. Handy for us forgetful folks. You can use both, too, of course.

See "Buttons" section at http://fortawesome.github.io/Font-Awesome/examples/