I'm a blogger, not a programmer. I don't make near enough money from it but calling it a tip instead of a donation has performed better.

Tip signals "payment for my work." Donation signals "gift."

People seem to be more inclined to actually fork over a few bucks if you signal "This is my work. I deserve to be paid for it." than if you signal "I would like gifts (or charity) from random internet strangers."