Tools that enable end-users to customize websites typically use a two-stage workflow: first, users extract data into a structured form; second, they use that extracted data to augment the original website in some way. This two-stage workflow poses a usability barrier because it requires users to make upfront decisions about what data to extract, rather than allowing them to incrementally extract data as they augment it.

In this paper, we present a new, unified interaction model for web customization that encompasses both extraction and augmentation. The key idea is to provide users with a spreadsheet-like formula language that can be used for both data extraction and augmentation. We also provide a programming-by-demonstration (PBD) interface that allows users to create data extraction formulas by clicking on elements in the website. This model allows users to naturally and iteratively move between extraction and augmentation.

To illustrate our unified interaction model, we have implemented a tool called Joker which is an extension of Wildcard, a prior web customization system. Through case studies, we show that Joker can be used to customize many real-world websites. We also present a formative user study with five participants, which showed that people with a wide range of technical backgrounds can use Joker to customize websites, and also revealed some interesting limitations of our approach.