Great comments so far!
I will chime in. Just for background, I just graduated from law school and am in the process of studying for the bar exam later this summer. My presumed speciality is Intellectual Property (copyrights, trademarks, etc), Entertainment law, and Civil Litigation. This is just for background and certainly is not intended to either be deemed as "legal advice". Nor do I intend to make my opinion any more valid than the other supported opinions that have already been expressed. I just want to make it clear that copyrights, particularly as they relate to music is very dear to me and has been my focus for the last few years of study.
Poor Man's Copyrights
There is a great deal of myth, lore and discussion about this method. The earlier comments about copyrights being granted inherently upon creation is spot on, in my opinion. Per the Copyright Act, you have copyright protection the moment your work is fixed in a tangible medium of expression (lyrics on a paper, music notation written out on paper, notation and/or lyrics on computer hard disk, the chalkboard, the song recorded on hard disk, tape, vinyl, digital tape ... you get the picture). Any tangible medium will suffice--a napkin even. Copyright protection is one issue. Registration of that copyrighted work is another.
Registration
There is only one (1) source that can register a work. It is the US Office of Copyrights. Not ASCAP, BMI, your songwriter's guild, etc. The only place to officially register your work is the US Copyright Office. The forms are fairly simply to fill; the fee is fairly small (currently $30). Registration of your work in the US Copyright Office creates a (legal) presumption that you are the owner of that work. This is bigger than you may imagine. The long and the short of it is that once you have a presumption in your favor, the opposing party has the burden of proof to disprove/refute your established legal presumption. So do yourself a favor and register your works. Plus, in most cases registration in the U.S. Copyright Office is a prerequisite to filing an infringement suit. And, without a registration you cannot get statutory damages (which for intentional infringement is up to $150,000 per infringement). So registration is a no-brainer.
What about this Poor Man's Copyright Thing? What does it get you?
The short answer is "it gets you nothing." You already have copyright protection inherently upon creation and fixation in a tangible medium. Mailing a tape of the song does nothing to upset that grant. Many lawyers say the poor man's copyright thing is pretty worthless ... and for good reason. The Poor Man's method may be, however, helpful in establishing a time of creation ... and presumably ownership. The large white elephant in the room, however, is that the method can be easily faked by taking a blank envelope, writing your own address on it, not sealing the envelope. When it arrives you put anything you want in it--at whatever date you want. Can the poor man's stuff be used in court? Yes, but not likely as substantive evidence (evidence attesting to be what it claims to be).
For example, you're in court trying to testify that you created Song X on XYZ date. You attempt to offer the sealed envelope as such proof. As strange as it sounds the mailed tape may not come in as direct evidence. It is "hearsay" ... an out of court statement offered for the truth of the matter asserted. There are exceptions to the hearsay rule, but in my opinion no exceptions apply to the above scenario. (perhaps the business records exception... but it's a stretch). The tape may come in, not as substantive evidence, but to impeach your testimony if you testify otherwise... or you may use the tape as 'non-hearsay' to refute a claim that you are lying about your stated date of creation... but the sealed tape, with all its previously stated flaws, likely will not come in as direct evidence to prove your date of creation... Though it may be helpful to you, personally, as a stamped date to jog your memory as to when the work was created.
What Evidence Is Likely to Come Into Court?
Testimony... by a living, breathing person who can attest to your date of creation--yourself included. (If pretrial, an affidavit from that living, breathing person). You can use the poor man's method as a way to date stamp the creation ... but you can do this with a simple note signed by both you and your witness... Heck you can even notarize it if you want. But, be warned that the notarization only attests to your identification. It does not go to the 'truth' of the document's assertions. So in the end, if you have an infringement suit, you will still have to show that you, indeed created the work in question. You will still have to offer evidence, usually by witnesses agreeing with that creation date. You will still have to show that the alleged infringer had access to the work to copy it. These are factual issues that (usually) a jury will decide, and as such they depend on your credibility as a witness and the strength of your evidence and presentation (i.e. your lawyer's skills).
What do you do About this Poor Man's Thing?
If you want to do it, be my guest. At worst, it will establish a date of creation to jog your memory, in the event you have to testify as a witness or sign an affidavit. However, don't fool yourself into believing that the Poor Man's method actually established a copyright.
Incidentally, I have done several searches in state and federal caselaw databases and I have yet to find any case that involved the use of such evidence. It appears not to exist... which I can only imagine helps the myth grow.
Do yourself a favor and register your work as soon as you can afford the $30 fee. If it's too high a price for one copyright, put several songs together as a "compilation" and register the compilation. Compilations make searching the copyright office for a single song title a bit more difficult, but the copyright protection is there all the same as if the work were registered individually. Have a witness or two or three verify your date of creation. Sign a simple document if you care. Personally, I think the Poor Man's method is not particularly useful, because you can create a date stamp in other ways (notarized document, witnessed document, date stamp on a hard drive or CD, etc). If you want to do it, it certainly does not hurt. But, it will not be a substitute for a registered copyright; it is no more proof of ownership of the copyright that without it; you have copyright protection inherently without it; and it has the tendency to make you complacently believe that it has greater value than it is really worth.
Just my 56 cents.
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