For example a piece of work that is not copyrightable in one country (even if it is the country of origin) may be copyrightable in another. Also in the US any work published before 1923 is in the public domain, however other countries are not bound by this year.
As far as this discussion is concerned, it is also debatable in some countries if the author is allowed to put his own work in public domain. Basically, there's no such thing as putting a work in the public domain, unless you don't mind limiting its usage (because if a piece of work is not accompanied by a license and is not in the public domain of the country you live in, you have no right to use it).
So if freedom is what you want, new-BSD or MIT are best. Plus, you keep getting the credit, which is nice.
For example a piece of work that is not copyrightable in one country (even if it is the country of origin) may be copyrightable in another. Also in the US any work published before 1923 is in the public domain, however other countries are not bound by this year.
As far as this discussion is concerned, it is also debatable in some countries if the author is allowed to put his own work in public domain. Basically, there's no such thing as putting a work in the public domain, unless you don't mind limiting its usage (because if a piece of work is not accompanied by a license and is not in the public domain of the country you live in, you have no right to use it).
So if freedom is what you want, new-BSD or MIT are best. Plus, you keep getting the credit, which is nice.