Abstract: The invention concerns presence of users, such as online presence in a broadcast domain. First one-way encrypted (e.g. hashed) presence information of multiple users is received (42) from their respective devices. Then for each received presence information, attempting to match (44) that received hashed presence information to a token of a stored set of tokens where each token corresponds to a user. The presence of a subset of the multiple users for which a matching token is in the stored set is determined, causing the generation (46) of an indication of the presence of one or more users of the subset of the multiple users. Aspects of the invention include methods, systems and software.

Abstract: A teleconferencing video system uses two cameras at each station symmetrically positioned on opposite sides of the optical axis between the speaker and the monitor used to produce an image of the listener. The two cameras are used to provide from the two images observed by the cameras a virtual image corresponding to the image that would be viewed by a camera located on the first-mentioned optical axis. This system permits eye contact to be maintained between a speaker and a listener at different stations whereby the feeling of intimacy is enhanced.