Millions of slide presentations are being authored and delivered with computer software every day. Yet much of the computer's power for these tasks remains untapped. Existing interaction techniques leave presenters wrestling with limited size computer displays to get meaningful overviews of their work. Without these overviews, they have trouble finding patterns in their data and experimenting with alternate organizations. They also have difficulty communicating the structure of large or complex talks to the audience and keeping the audience oriented during unexpected transitions between ideas. A natural solution is Zoomable User Interfaces (ZUIs) since they offer the capability to view information at multiple levels of detail and smoothly transition between ideas. This work presents two ZUIs, Niagara and CounterPoint, for authoring and delivering slide presentations.

Niagara is a ZUI workspace for authoring presentation content with techniques to improve authoring in the zoomable environment. Empirical evaluations of ZUI-based authoring tools revealed performance improvements and subjective preferences over folder-based interfaces for organization tasks. Users were 30% faster with ZUIs than with folders in completing a simplified shape organization task. Some classes of users were also faster with ZUIs than with folders in completing a text-based organization task. Users performing both tasks exhibited a strong preference for ZUIs over folders.

CounterPoint provides a number of features to simplify the creation and delivery of ZUI presentations. The effects of these presentations on the audience were evaluated in a controlled comparison of presentations with slides only, slides with spatial layouts, and slides with spatial layouts and animation. The study revealed a strong subjective preference and higher ratings of organization for presentations with spatial layout.

Feedback was also gathered from presenters who used CounterPoint to deliver over 100 real-world presentations. They indicated that CounterPoint helped them communicate overviews and multi-level presentation structures. More experienced CounterPoint presenters also found that CounterPoint helped them keep the audience oriented when navigating the presentation in response to audience feedback.