Although there are many on-line stores, where potential e-shoppers can purchase desired products by visiting a few web pages, finding the right product to purchase is quite a tedious task. On-line stores usually offer a limited set of ill-described products, presented in a way that prevents side-by-side comparison shopping.

In this chapter, we present a comparison chart building approach that is based on information extraction wrappers. The novelty of our approach consists of the usage of the Conceptual Graphs knowledge representation and reasoning formalism, which naturally supports both the wrapper induction and the wrapper evaluation tasks through the generalization, specialization and projection operations. In addition, the graphical representation of Conceptual Graphs makes them a proper technology for creating visual, wrapper management programming environments.

Finally, we present the Aggregator, a prototype system based on our approach, that allows the user to quickly and visually train information extraction wrappers and use them to built comparison charts of arbitrary detail, gathering information about similar products from multiple known sites.