2. Any software released under the GPL, LGPL, or other open source licenses.
3. The stuff that makes Bill Gates' life sad.
Giving the public the ability to modify, improve, and fix the program itself. Allowing the creator of the program to not have to find a way to fix the program himself and allowing more patches and improvements to the software.
Also allowing the public to be able to port the program onto other operating systems, so that dual-booters who can program will make a windows version of an awesome GNU/Linux/BSD/Solaris program.
See also open source
GPL is an example of an open-source license.
An idea, invention, project,that is open to general public to allow changes in anyway (Preferably for the better)
Lincolndogs is an open source animation project
Dr Malik applies an open source policy on all his inventions and innovations