Most record companies, for instance, are wary of samples from other works and seek permission from the original mechanical copyright owner. In literary reviews, quotations from the original work are expected - but since these quotations only represent a tiny tiny fraction of the whole work, I can't think of any case where reviews have been subjected to court tests. Incorporating literary passages into other works (without citation) though, has been the basis of many court cases.

We are in a shifting paradigm. Viral marketing often depends upon the easy reproduction and dissemination of copyrighted works where the copyright holder foregoes their rights for other benefits. Where ubiquitous visibility is a marketing tool, copyright is often forgotten.

Within 10 years or less, the copyright landscape will have totally changed - however the EU tries to legislate it.  The genie is out of the bottle.

We may reach a point where it is understood that nothing is truly original - every creative work depends on the audience understanding the references. Because you have to know the language before you can understand it, and all the works that have gone before have built that language.

There may be faster steps that appear to be more original by their disjunctiveness, but over time all steps can be traced back to the start of the walk.

As I said, it is a fine line, and can only be tested in court. I think we owe it to Jérôme to avoid that testing if possible.

You can't be me, I'm taken