Visualization allows rapid overviews to be presented.
Direct manipulation of these visualizations allows rapid feedback, making data exploration a highly interactive process. Visual query languages that work together with direct manipulation increase the expressive power of user interaction. I have recently been working on algorithms to increase the size of datasets that can be interactively explored. I plan to apply these techniques to exploring personal histories of Web browsing, email, calendar, phone calls, and other document interactions. This kind of information is more structured than most of the Web currently is, but less structured than traditional databases.