Just posted this (with an embarrassing title typo) in a comment thread over at Linux Weekly News. Thought I'd repost it here. Enjoy…
First off, I Am Not A Lawyer, and nothing I say constitutes any sort of legal advice. That said, here's my lay opinion on the reasons why releasing software and other copyrightable works "into the public domain" is a bad idea.
Lawyers I trust tell me that the whole concept of "releasing into the public domain" is of doubtful validity in US law. There are various ways spelled out in US law that a copyrighted work can enter the public domain. One of these is "abandonment" of the copyrighted material. But it is not clear to these attorneys that you can explicitly abandon a copyrighted work.
One of the rights protected by copyright is the right of attribution. If I were to take public domain code and claim to have written it, this would, I believe, be perfectly legal---as long as it wasn't part of some other actionable offense. If you are proud of anything in your code, you probably want to avoid that.
One of the things a good license tries to do is to control legal risks of release of material. Disclaimers of warranty and liability (for what they're worth) and legal terms of use can help to protect the author from expensive and potentially damaging litigation.
License notices and copyright notices are a way of protecting the user of a copyrighted work from a malicious author. Under current US and International law, published work defaults to "copyrighted" even in the absence of any copyright notice. The placement of copyright and license notices specify exactly which rights are granted by the author, and under what terms. Anyone who uses code from a large "public domain" release may run a substantial risk that the author may say "oh, but I didn't mean to release that" to a court. I wouldn't want to be defending myself from a copyright infringement charge over this.
Conversely, if an author publishes copyrighted work related to her previous public domain work and inadvertently omits the copyright notice, it seems easy for someone unscrupulous to claim that it was part of the public domain release.
Like I say, I'm not a lawyer. But for all of these reasons, I don't plan to release any more code for public use without licensing it somehow.
(B)