Don't put your software in the public domain

[Random832]

On Fri, Jun 3, 2016, at 22:02, Steven D'Aprano wrote:
> (I am surprised that it takes so little to grant end-user usage
> rights, but IANAL and presumably the FSF's lawyers consider that
> sufficient. Perhaps there are common law usage rights involved.)

Technically, there are statutory usage rights; 17 USC 117 (a) (1):

(a)Making of Additional Copy or Adaptation by Owner of
Copy.—Notwithstanding the provisions of section 106, it is not an
infringement for the owner of a copy of a computer program to make or
authorize the making of another copy or adaptation of that computer
program provided:
(1) that such a new copy or adaptation is created as an essential step
in the utilization of the computer program in conjunction with a machine
and that it is used in no other manner, or
(2) that such new copy or adaptation is for archival purposes only and
that all archival copies are destroyed in the event that continued
possession of the computer program should cease to be rightful.

The proprietary software industry's continued ability to make demands in
an EULA rests on a rather shaky (though less than it was in the
box-full-of-disks days) theory that buying software does not in fact
make you the "owner of a copy", something that open-source types don't
tend to claim regarding their own software.

(IANAL either of course)