Bitcoin has been a particularly efficient solution for tips and donations in several cases. Sending a payment only requires one click and receiving donations can be as simple as displaying a QR code. Donations can be visible for the public, giving increased transparency for non-profit organizations. In cases of emergencies such as natural disasters, Bitcoin donations could contribute to a faster international response.
Imagine listening to Internet radio paid by the second, viewing web pages with a small tip for each ad not shown, or buying bandwidth from a WiFi hotspot by the kilobyte. Bitcoin is efficient enough to make all of these ideas possible.