By now most people who read blogs will have watched the JibJab political spoof song, which is unfortunately becoming another classic example of copyright laws being used to destroy free speech.
The song parodies the famous Woody Guthrie classic — This Land is Your Land” — or, does it satirize it? This may sound like semantics, but according to U.S. copyright law, parody is an authorized use of copyrighted material, but satire is not!

The germ of parody lies in the definition of the Greek parodeia . . . as “a song sung alongside another.” Modern dictionaries accordingly describe a parody as a “literary or artistic work that imitates the characteristic style of an author or a work for comic effect or ridicule,” or as a “composition in prose or verse in which the characteristic turns of thought and phrase in an author or class of authors are imitated in such a way as to make them appear ridiculous.” For the purposes of copyright law, the nub of the definitions, and the heart of any parodist’s claim to quote from existing material, is the use of some elements of a prior author’s composition to create a new one that, at least in part, comments on that author’s works. If, on the contrary, the commentary has no critical bearing on the substance or style of the original composition, which the alleged infringer merely uses to get attention or to avoid the drudgery in working up something fresh, the claim to fairness in borrowing from another’s work diminishes accordingly (if it does not vanish), and other factors, like the extent of its commerciality, loom larger. Parody needs to mimic an original to make its point, and so has some claim to use the creation of its victim’s (or collective victims’) imagination, whereas satire can stand on its own two feet and so requires justification for the very act of borrowing. [footnote: Satire has been defined as a work “in which prevalent follies or vices are assailed with ridicule,” or are “attacked through irony, derision, or wit.”] (Via Eugene Volokh.)

I have a legal education and Varius is a classics scholar. Perhaps between the two of us we can figure out what’s going on.
In a truly fair world, none of this should matter, because Guthrie himself clearly manifested an intent to give the song away:

“This song is Copyrighted in U.S., under Seal of Copyright #154085, for a period of 28 years, and anybody caught singin it without our permission, will be mighty good friends of ourn, cause we don’t give a dern. Publish it. Write it. Sing it. Swing to it. Yodel it. We wrote it, that’s all we wanted to do.” (From Jesse Walker, via Eugene Volokh.)

This kind of nonsense irritates me to no end. Certain things ought to be in public domain — especially “This Land is Your Land.”
Sheesh! Next they’ll be telling me I can’t satirize parody satirize or parody Air America!
Either neither or none!