Not sure which forum this should go in. This subject came up in a question I asked and it reminded me that "Fair Use" is one of the most misunderstood concepts. I was once in a job position that required me to stay informed on some of the nuances of fair use and copyright.  One common myth that never seems to die is that "if you use less than [insert any low amount] it is fair use and you cannot be sued.  This is an an absolute lie and will get you sued. While it is true that the larger the amount sampled or used will increased the liability, there is no preset timeframe.  A half second sample of James Brown screaming "Heeeey!" is worth a lot more than a full song by me.  Anyway, in one workshop i was required to take, they passed out a very useful comic book on the topic published by Duke Law School.  It is very easy to understand and clears up a lot of misconceptions.  The PDF version is free to download:http://web.law.duke.edu/cspd/comics/

Interesting! Thanks for sharing.

Even though it is presented as a comic book, this legal article, like most such endeavors, clarifies nothing and complicates everything. The philosophical message that copyright law is out of balance, is well received, but the idea that "artists" can have much influence on the process of copyright legislation and litigation is ludicrous. The big money in art is in mass media, and the artist is almost never the important player in how mass media is marketed or exploited. The rights culture is part of the corporate exploitation side of the art business not the creative side, and the last time Congress listened to an artist in such matters we got the Sonny Bono Copyright Extension Act of 1976.
 
As a point of law fair use seems to have definable parameters, even tests, but as a matter of practice the ambiguity of those tests and the apparently discordant interpretation of those tests against the facts in litigation before various courts and judges leaves the artist with very little confidence. As a practical matter if you plan to use fair use as a defense in an infringement action you have probably already sold the family farm for legal expenses with very little chance of ever recovering your costs and a good chance of losing your shirt. The most aggressive and expensive lawyers in copyright law work for corporate plaintiffs.

As I understand it, the fair use applies mainly to educational use in such things as music appreciation and listening type classes. This is so the teachers don't have to "clear" every song they use in their curriculum.
 
Of course there are more but very limited fair uses..... and this entire topic is a deep one, subject to many opinions and interpretations, but the only ones that really matter are those of the particular judge and jury hearing your case in a court of law.
 
IMHO, the best option is to either obtain the rights or avoid using other folk's copyrighted material.

Slartabartfast..BINGO! The laws are setup so that you better have deep pockets even if you are right. I don't think the book means to be ambiguous. I think it means to drive home the point you made but also add false hope. Copyright laws have gotten progressively more slanted. The Sony Bono act did help matters. Look at a documentary from the 60's and 70's and one made now and drastic differences stand out. The tv running in the background was not seen as infringement but just an incidental part of history.

Guitarhacker, the history of fair use cases in court is fascinating ( at least to media nerds as myself). I know one case involved a review of an interview with Gerald Ford. The only part anyone cared about was why he pardoned Nixon and the review included that excerpt, claiming fair use. They lost because it was deemed that review damaged the product by letting the cat out of the bag.

dubdisciple
 The Sony Bono act did help matters. 

My point was that relative to the average citizen's interest and benefit from limiting the term of copyright so that works would enter the public domain, the Bono act made things much worse. It retroactively extended copyright protection to existing works by decades hence the "Micky Mouse Protection Act" moniker that it clearly deserved. The only significant relaxation of the exclusivity of the copyright monopoly, which in practice is usually held by immortal corporations, was to permit libraries to make archival copies of works that have no marketable value (a mere assertion that they do have value by the copyright holder seems to block this) and to allow small eating establishments to play the radio without paying the performing rights organizations.
 
A fairly good characterization of the law can be found in a dissenting opinion by Justice Breyer when it was found constitutional.
http://www.copyright.gov/docs/eldredd1.pdf
 

Actually that was a mistype..I meant to say it did not help matters...oops

Recently, I tested for my amateur radio license and one aspect of the test was rules and regulations. One of those was in regard to the broadcast or rebroadcast of music.  No music of any kind, from any source, including background music is permitted. So if you're in your home or car and need to talk on the radio, and you have music playing on the FM radio... you have to turn the FM off to prevent the inadvertant rebroadcast of music on the ham frequencies..... I imagine this is related closely to copyright laws......  The only exception to this is if you are talking with the folks on the ISS and they happen to have music playing in the background.... that is permitted.

Guitarhacker, It is a copyright issue.  The rules border on ridiculous.  i understand the need to protect intellectual property , but it does make documenting history a lot more complicated.  Imagine doing a documentary on something like Woodstock today. the clearance for all the music puts such documentaries out of the hands of all but the wealthiest. Even when I am editing video of events, we take out the music that was actually playing and sub stock music or music we have rights to put in video. It makes everything horribly inaccurate.