Canonical has long made the most popular desktop version of Linux, but actually making money off Ubuntu is easier said than done. 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. The options are "Make the desktop more amazing"; "Performance optimisation for games and apps"; "Improve hardware support on more PCs"; "Phone and tablet versions of Ubuntu"; "Community participation in Ubuntu development"; "Better coordination with Debian and upstreams"; "Better support for flavours like Kubuntu, Xubuntu, Lubuntu"; "Tip to Canonical—they help make it happen."

By default, the page puts in $2 for each, a total donation of $16. Depending on what you contribute, Canonical shows what else you could buy with that money. Bizarrely, $200 equates to "the price of a pair of sexed Emu chicks." The most you can donate at once is $1,000, or "the price of an eight year-old dromedary camel."

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.

Canonical accepted donations prior to this week, but in a blog post about the move yesterday, Canonical VP Steve George wrote "we're making it easier for people to financially contribute to Ubuntu if they want to."

"By allowing Ubuntu users to choose which elements of Ubuntu they’re most excited about, we’ll get direct feedback on which favourite features or projects deserve the bulk of our attention," he wrote. "We’re letting users name their price—depending on the value that they put on the operating system or other aspects of our work. That price can, of course, be zero—but every last cent helps make Ubuntu better."

Ubuntu isn't the only Linux desktop distribution looking for donations. Linux Mint (which is based on Ubuntu code) does as well, for example. While Canonical gives away its software for free, it is a private company rather than strictly a community project, and some people may not feel comfortable donating to a business rather than a charity.

Although Distrowatch shows Ubuntu as being only the third most popular Linux distribution (after Mint and Mageia), a more extensive and likely more accurate gauge of real-world use comes from a Wikimedia traffic analysis report. Over the most recent 12-month period, Ubuntu accounted for 1.1 billion hits to Wikimedia, with the next-most popular Linux desktop distribution—Red Hat's Fedora—accounting for 36.7 million.

Yet after eight years in business, it's not even clear whether Canonical is profitable. The company has branched out with business products and support, struck distribution deals with desktop hardware vendors, and is eyeing mobile devices, but it doesn't seem to be enough. Witness a recent move to add Amazon search results into Ubuntu's desktop search tool, in order to get money through affiliate links.

Some users were disturbed by the Amazon move, telling Canonical Founder Mark Shuttleworth so in the comments on his blog. But even users who don't want Amazon search results when they're searching for a file on their desktop may want to support Ubuntu financially. Providing an easy-to-find donation page and the option to direct money to whichever part of Ubuntu development one prefers seems like a reasonable way to raise money without affecting the behavior of the operating system itself.