WebNC is a system for efficiently sharing, retrieving and viewing web applications. Unlike existing screencasting and screensharing tools, WebNC is optimized to work with web pages where a lot of scrolling happens. WebNC uses a tile-based encoding to capture, transmit and deliver web applications, and relies only on dynamic HTML and JavaScript. The resulting webcasts require very little bandwidth and are viewable on any modern web browser including Firefox and Internet Explorer as well as browsers on the iPhone and Android platforms. Categories and Subject Descriptors H.5.4 [INFORMATION INTERFACES AND PRESENTATION]: Navigation Keywords Web application sharing, web navigation, real-time collaboration, co-browsing