Bad Idea No. 5: Under the Public Domain

It is not wise to licence one’s code under the Public Domain because the Public Domain is not widely understood or accepted internationally, and because licensing code under the Public Domain may not be possible. Rick Moen gives more reasons under “Public Domain” in the Licensing and Law section of his knowledge base.

If you’re interested in making your software as-close-to-PD-as-possible, you should choose the MIT/X11 Licence or a similar licence such as the ISC licence.