MarketingProfs.com has published an article I wrote on documenting market/product requirements. The article is entitled, "How to Guarantee Product Failure". You can view it at:
http://www.marketingprofs.com/4/cauvin1.asp
They will put the article in their archives next week, after which it will be accessible only to registered members. My company has published a copy of the article at:
http://www.cauvin-inc.com/articles/ProductFailure.htm