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.