OT - Closing Off An Open-Source Product

[Lulu of the Lotus-Eaters]

|1.3 In particular, if I take a public domain work, and the only change I
|make to it is to add my copyright notice, I have obtained a copyright on
|absolutely nothing.

On the other hand, if I take a public domain work, change one line, or
one word, or one character, then slap a copyright notice on it, I have a
legitimate copyright on the derived work.  Someone is free to do what
they want with the original (is they find it); but they do not have the
right to use my derived work unless they are licensed to do so.

Many open source licenses operate quite differently from the public
domain works.  Licenses like the GPL (and the MPL and BSD to a lesser
extent) place certain obligations on users who want to use the original
(licensed) works as the basis for derived works.  For the GPL, in
particular, the intent is that derived works must themselves be made
available for further derivation by still other parties.