Oh, hey you're in the thread. You're really confusing matters by using the term "Public Domain" in a way that really doesn't mean what you are trying to say (though I'm not at all sure what that would be). Please see the post I made elsewhere in this discussion that may clear up matters a little:
https://news.ycombinator.com/item?id=8792829(FYI, when I speak of "rights" in this post, I mean "legal rights", which I personally distinguish from the ethical ideas of "right" and "wrong"--I'm just explaining legality, there is no "ought" in what I say here)
> What I was not aware of is that the copyright notice required by BSD is useful only in asserting the right of the copyright owner to swear away virtually all of the protections normally granted by a copyright notice. It is a legally castrated copyright.
Um, what did you think a license would do? That last sentence, it's pretty much exactly the definition of what a copyright license does (if a little strongly worded).
Copyright is automatic. It only affects works (in your case, written code), not ideas (such as algorithms). You start out with all these rights about copying, distributing and broadcasting that particular work. These rights are exclusive, they belong only to you. That is default copyright, when you don't license anything.
Indeed exactly what a license does, is "castrating" (if you will) your copyrights. You can (partially) grant these rights to others, under certain circumstances, thereby diminishing the value of your own exclusive rights. That's what it does, a license defines under what circumstances you give up your right to exercise your copyrights, with respect to other people.
You start out with full exclusive rights, and a license formalizes how much and under what circumstances you are willing to chip away those rights and share.
Yet again, I must stress, copyright only applies to a "work"--a legal term, in this case referring to the written code of your project, and in general specifically not referring to ideas.