The way copyright lawyers talk about the public domain as something works “fall into” when the copyright terms finally expires, it sometimes sounds like some kind of trash heap. But that couldn't be further from the truth: The public domain is a fantastic resource for learning, creativity and innovation—our cultural commons.

We were very happy to learn that Flickr has released a feature this weekend that allows any uploader to use Creative Commons tools to take easy affirmative steps to support that resource. Flickr users can now easily mark their photos as public domain materials in two ways: either by using a Public Domain Mark (for images already available without copyright restrictions), or using the CC0 waiver (to release whatever restrictions might be in place).

This announcement comes after SpaceX, the private spaceflight company that operated a mission for NASA earlier this year, said it would release photos without any restrictions. That was big, but Flickr's technical update supporting it could have an even greater impact.

First some background. The free release of SpaceX photos is an extremely welcome development for public domain advocates. The company's successful flight in February produced beautiful images, including some of Earth from space. Those sorts of photos have traditionally been in the public domain because NASA and its employees, as members of the U.S. government, are ineligible for copyright in works created in the course of their job. As a result, decades of space imagery from the Blue Marble to moon landing video to space selfies has been free for all the public to use by default.

That arrangement, though, was jeopardized by private companies like SpaceX. As a private corporation, it could invoke copyright to lock down its photos for 95 years. After a series of calls from activists and advocates for the SpaceX images to be released under less restrictive terms, the company created a Flickr repository with dozens of striking photos, all released under a Creative Commons Attribution-NonCommercial license. Those terms are more permissive than all-rights-reserved copyright, but are still a far cry from the true public domain. That disappointment was averted when a Twitter user prodded SpaceX CEO Elon Musk to instead release the photos fully into the public domain, and he unexpectedly agreed.

(This isn't the first time Elon Musk has adopted a position on so-called intellectual property issues that is more permissive than mainstream expectations. Last year he announced that his electric car company, Tesla, would make its patents available, even to competitors who wish to use the technology.)

SpaceX hosts a copy of the photos on its site, where they are clearly released under a CC0 waiver, and so available for any use. But the Flickr repository was set instead to the most permissive license available at the time, which still required attribution.

Flickr's announcement this weekend takes a crucial final step: the public can now benefit from being able to use and share SpaceX photos, and a wealth of other images that people can choose to release under equally permissive terms.

What is more, Flickr’s expanded support for Creative Commons tools will give a major boost to the machine-readable aspect of the license. When images are appropriately tagged with licenses, for example, search engines can index that information, letting other users find the works they want with the freedoms they need them to carry. That has knock-on effects, too. Most notably, Wikipedia is illustrated largely with images in the public domain or under certain Creative Commons licenses—many of which can find their way to the site through an automated import from Flickr. That automation would be impossible without platform-level support for indicating licenses.

Wikipedia itself is a pretty futuristic application when viewed from just a few years back, and it's a good example of the drawbacks of long copyright terms and "thick" restrictions. Photographers snapping photos a few decades ago might be perfectly happy to allow those photos to show up on Wikipedia—especially considering that they measurably increase the quality, readership, and engagement of articles where they appear. But because it did not occur to those photographers to release their photos so that they could be used by as-yet-unimaginable future free collaborative encyclopedias, those images are by default off limits for many decades to come.

Flickr’s tools offer a better default option, one that allows photographers to help ensure their work will be available for use in the next Wikipedia (or any other venue, including those that we can’t anticipate). The more permissive the license creators choose, the more likely it is to just work in those new venues—and it doesn't get any more permissive than public domain. It's great then that SpaceX is doing its part to help grow the public domain, and just as exciting that Flickr is allowing everybody else to join in.

Images by SpaceX, used without permission.