Discovering.
The web browser extension provides a mechanism for alerting the user to web pages that might be good candidates for data extraction. When certain forms of structured, semantic metadata are detected on the current web page, the icon of the extension’s toolbar button is updated to inform the user of this fact. As shown in Figure 2, the normal icon is a dull grey funnel, but when semantic metadata is detected, the icon is changed to a bright green funnel with a red plus sign overlay. By changing the colour and shape of the icon, we are able to notify the user of potential data sources without distracting from the web browsing experience. Other notification techniques, such as pop-up alerts, would be much more noticeable but would also disrupt and annoy the user. In contrast, our subtle icon notification method promotes awareness without user interference. Also, the use of toolbar icons to display additional information conforms to a commonly used design pattern for web browser extensions and should be familiar to most users.