How does that happen?

I just spent a good 10 minutes typing up a follow up to my Holy Trip. Then as my fingers were flying across the keyboard, my paragraphs of text disappeared. What key did I hit to make that happen? I really would like to know since it has happened to me while writing out lengthy e-mails as well. It isn't like I am some mad typist. I only type about 35 words per minute with lots of errors. I watch the keyboard half the time too. I stay on the home keys and the main keyboard. I don't have stray fingers near the delete key or backspace since they are near punctuation I don't use. The program saves a draft of what you type. However, for some reason when I went to the draft it was blank. Sigh, now I don't have the time to whip out another version of my follow up. I will have to come back to it later. In the meantime be careful when your typing. Beware the mystery key on the central keyboard that deletes your work.