Hmm.. maybe I'm wrong, but doesn't paypal disallow non-charities from collecting donations? And they often end up freezing the account?

Here's the link stating that google checkout does not allow "donations" unless you're tax-exempt: http://www.reddit.com/comments/gx7br/google_emulates_paypal_...

I can't find the related news article for paypal offhand.

Given that anyone donating is presumably using nginx somewhere would be very easy for them to restructure this as "paying a voluntary license for the use of nginx at a $ amount to be decided by the customer"

They should do that and avoid the pain of a paypal frozen account.

Just what I was looking for - thanks!