PDI:About

From PDI

Public Domain Ideas (PDI) is an extremely simple concept. United States patent law states that an invention cannot be patented if it has previously been "described in a printed publication." In the USPTO's own words, "If the invention has been described in a printed publication anywhere in the world, or if it was known or used by others in this country before the date that the applicant made his/her invention, a patent cannot be obtained." Since documents appearing on the internet are considered by the USPTO to be "printed material," ideas and inventions described here are explicitly placed into the public domain and cannot be patented.

In other words, PDI is to ideas what open-source software is to code.

The best way to learn more about PDI, and about patents in general, is to read the PDI FAQ.