1. A computer-implemented method comprising: detecting, by a computer system, user input directed to an interactive surface that is displaying information; obtaining, by the computer system and from one or more detector units, observations of a physical environment around the interactive surface, wherein the physical environment includes one or more unknown users who are physically located within a threshold distance of the interactive surface; accessing, by the computer system, data that correlates a plurality of unique features to a plurality of known users; selecting, by the computer system, one or more users from among the plurality of known users based, at least in part, on a comparison of the one or more observations with the plurality of unique features, wherein the one or more selected users are identified as likely being the one or more unknown users who are observed as being located in the physical environment around the interactive surface; accessing, by the computer system, one or more profiles for the one or more selected users identifying, at least, preferences for the one or more selected users; determining, by the computer system, an update to apply to the information that is being displayed on the interactive surface based, at least in part, on (i) the user input, (ii) the one or more selected users, and (iii) the one or more profiles; and displaying, by the computer system, the update on the interactive surface.