in reply to
Learn vi/vim in 50 lines and 15 minutes
In beep mode, no matter what character you try to press, vim beeps at you. Beginners enter this mode all the time; experts enter it only once every few minutes. Entering beep mode is nearly always unintentional; exiting beep mode is usually just as accidental. If you work in an office, and use vim, you should consider reducing the volume of your machine, or getting a set of headphones so as not to annoy the emacs users nearby.