Functional vs. Non-Functional requirements

Since many of us are struggling with the difference between F and NF requirements (and we're certainly not alone), I'd like to submit two references that might help - a first one that gives verbal arguments and a second one that list categories to consider:

- http://lists.ebxml.org/archives/ebxml-requirements/199912/msg00008.html

- http://shambhu.blogspot.com/2008/10/functional-vs-non-functional.html