We all know Greg Gillis's invocation of the fair use principle in justifying the use of samples in Girl Talk's Feed The Animals is dubious at best.
In an exorbitantly detailed, carefully argued blog post, The Future of Music Coalition has broken down the legal precedents of sampling in relation to Girl Talk. The post argues that though Feed The Animals is difficult to justify legally, it would be virtually impossible to produce through means sanctioned by law:
If Girl Talk had simply recorded an album of covers – faithful reproductions of complete songs – this blog post wouldn’t be necessary. As long as he paid royalties to the original composers, all would be swell. But under current copyright law, copyright owners maintain the right to say "yes" or "no" to derivative uses of their work. In other words, samples. So, to properly clear and license all the samples on Feed the Animals, Girl Talk would have had to first figure out who owns each copyright (which is a huge problem on its own), and then gained permission from both the sound recording copyright owner and the composer/publisher for each work he sampled. If you’re keeping track, that’s about 600 green lights and zero stop signs.
Keeping in mind that major labels usually have copyrights to music and not the artists, it's hard to imagine that major labels would be fine with all this unpermitted sampling if they could dissect each instance a sample was taken.
Yet, considering how difficult it would be to obtain the rights to all the samples on Feed the Animals—let alone Girl Talk's ability to pay to acquire those rights—it's clear that an ineffecient system is in place for sampling artists and artists who are sampled alike. [Future of Music Coalition]