Source: http://www.pia-frauss.de/imp/cu.htm

Conditions of Use
All of my fonts are free for private and educational use.
Non-profit use is free, too, but needs to be approved by me (I've recently discovered that there can be fundraisers I might by no means wish to support).

What is private use?
Private use is whatever you do for yourself, or a relative, or a friend, when neither yourself, nor those you work for, are making money out of your use of the font.
Examples:
You may use my fonts on a self-designed website, even if that website is a commercial one. Same goes for self-designed business cards.
You are very welcome to use my fonts when desiging your personal greeting cards, invitations, websites, avatars etc., and even those of your relatives and friends, as long as designing cards, websites etc. isn't part of your business, and you aren't making money on a regular basis out of such designs.
You may use the font in yearbooks and programs for plays you enact at your school/college -- that would still be considered educational use.