The presenter is creating a work and sharing it free of charge—therefore it is not a for-profit situation. …
Sites that request donations expect their readerships to view their sites the way computer users regard shareware: If you like it, pay us a few bucks, which will encourage us to keep up the good work. But content isn’t the same as software; it is usually a diversion, not a utility, which alters its worth.
—When you make me pay, I’ll pay, May 23, 2002