New submitter major_lima sends this excerpt from Ars:
"When a typical user downloads Ubuntu for free and installs it on a computer with a Windows license that the user did pay for, Canonical gets nothing in the form of payment. There's nothing wrong with that — this is the open source world, after all, and many people contribute to Ubuntu with code rather than money. But starting this week, Canonical is presenting desktop OS downloaders with an optional donation form. ... 'Pay what you think it's worth,' and 'Show Ubuntu some love' are among the messages users will see, and downloaders can direct their donations to specific parts of Ubuntu development. ... Once you donate, the Ubuntu desktop starts downloading. Or, you can just skip the donation and download the OS for free, just as you always could. For some reason, the donation page is not presented to Ubuntu Server users."