The Campus Mobile project explored how PDAs and innovative interfaces can improve interaction during lectures and in small meetings. These mobile computers (small PCs or PDAs) are nomad mediators that provide the link between the public space and the user's private space. A lecturer uses an augmented whiteboard to annotate her presentation, while the slides and annotations are broadcast in real time to the students' PDAs. The students can also annotate the presentation. They can then replay the lecture at their leisure. We developed and tested the user interfaces for the interactions on the whiteboard and on the PDAs, the data formats to store the annotations and temporal data, and the network protocol for reliable wireless broadcast transmission. Small meetings have a very different interaction pattern. Instead of a lecturer that transmits knowledge, the participants collaborate in modifying documents. We developed groupware services that encourage these interactions and show how the different interaction patterns imply different network usages.