Quick key and the Petname system

I have come across an interesting article An Introduction to Petname Systems. It echoes with a quick key feature I am building, which associates a short phrase with frequently used URL. For example phrase 'amex' can be used as the key to the 'American Express' web site. The main goal of the article is in security (against phishing). While for MindRetrieve the goal is to make a slick user interface. Nevertheless it helps me to understand what I am doing, an implicit system for user to assign petname to items!