Discovery and Presentation of Community Membership at a Physical Event

In many contexts, an individual is part of a large group gathered together and may not know that there are others present that she knows. This disclosure describes techniques that, with user permission, automatically identify others present at an event that the user has something in common with. With user permission, attendees at an event are identified and their attributes are retrieved from online profiles. Subsets of attributes are identified that correspond to small groups and users that members of the subset are notified of the presence of others in the subset. A user interface is provided that uses color, shape, or other attributes to make it easy for a user to identify others in the crowd that they may know