A presence system and method are described herein which infer a person's level of participation in a telephone call (e.g., multi-party conference call, one-on-one telephone call, collaboration session). In one embodiment, the presence system collects presence information about one or more activities of a person while they are also participating in a telephone call. The presence system aggregates and analyzes the collected presence information to determine a telephony/conference activity presence state which is then published to watchers and/or an automated interaction management system in order to inform them if the person happens to be an 'active participant' or a 'passive participant' in the telephone call. The watchers and/or the automated interaction management system can then use this information as a guide to determine if the person is likely to be able to respond to another interaction while that person is also participating in the telephone call. The inference is that a person who is 'passive participant' is substantially more likely to engage in an IM or even a second phone interaction with another person (e.g., watcher) then if that person was an 'active participant'.