Copyright Information: Creative Commons Licensing and the Public Domain

Things that are in the public domain may be used without limitation. But what about information on the Internet? There exists a misconception that information freely available on the web is not under copyright protection. Availability and copyright are NOT the same thing. Remember that the vast majority of content on the web, though freely available, is still protected by copyright. The copyright term is very long. However, because the copyright laws changed several times throughout the 20th century -- with changes to the law sometimes being retroactive -- it can be very challenging to figure out if a given piece of content created in the 20th century is in the public domain or not.  

The easy case: If the content was created/published before 1923, it is in the public domain.

For material published after this date, it gets REALLY, REALLY complicated.  This Cornell University Copyright Information Center chart, Copyright Term and the Public Domain in the United States, provides detailed information about all of the possibilities. This slider, Is It Protected By Copyright?, provides simplified information for the most common scenarios.

Still, when you're not sure, it's best to assume that an item is under copyright and you should seek permission to use it.

These websites can help you determine whether or not a particular work is in the public domain.  If you are not sure whether a work has passed into the public domain, however, it is always better to seek out permission before using the material.

Works created by the Federal government (and some state governments) are not subject to copyright. This applies to works created by employees of the United States government in the course of their duties.

Unfortunately, there are some exceptions:

• Works produced by contractors or freelancers employed by the government are likely to be copyrighted.
• Works produced by some agencies (eg. the post office) may be subject to copyright.
• Government websites regularly feature art and imagery that were purchased or licensed by the government. Do not assume that it's not subject to copyright because it is on a government website.
• The government can own copyrights that are transferred to it.
• Logos of government agencies might be subject to trademark law even though they are not copyrightable.

State laws vary. Harvard University has a great resource for helping to figure out the relevant laws in each state.