Abstract: Among other things, a user can determine, from aggregated transaction data, private information about a transaction of another party. The other party is associated, in a shared social network database, as a contact with the user. The activity of the other party is related to an activity or contemplated activity of the user. The private information is from a source that is controlled independently of the shared social network database and the aggregated transaction data.

Abstract: Among other things, a user, who is engaged in a commercial activity on a commercial online site, is exposed to computer-stored information that (a) is associated with another user of the online site, (b) would otherwise be private to the other user, (c) relates to the commercial activity of the user, and (d) is controlled by the site.

Abstract: Among other things, a user, who is engaged in a commercial activity on a commercial online site, is exposed to computer-stored information that (a) is associated with another user of the online site, (b) would otherwise be private to the other user, (c) relates to the commercial activity of the user, and (d) is controlled by the site.

Abstract: Among other things, a user can determine, from aggregated transaction data, private information about a transaction of another party. The other party is associated, in a shared social network database, as a contact with the user. The activity of the other party is related to an activity or contemplated activity of the user. The private information is from a source that is controlled independently of the shared social network database and the aggregated transaction data.

Abstract: Among other things, a user of a site is provided access to information associated with a person who has entered, on a shared social network (SN) system controlled independently of the site, a consent to permit information of the person to be accessed by the user at the site. The information is displayed to the user of the site only in accordance with the consent. The consent is effective without requiring any action by the user of the site.

Abstract: Among other things, a user of a site is provided access to information about a person to whom the user has a connection. The connection is stored in a shared social network (SN) system controlled independently of the site. The information is displayed to the user of the site only in accordance with a permission of the person for whom the user has the connection.

Abstract: Through a user interface on a computer, a user is enabled to define questions to be answered by attendees of an event, the answers to the questions being indicative of connections corresponding to pairs of attendees, a computer receives answers to the questions from the attendees through a user interface, and based on the answers, provides information to attendees to facilitate face-to-face interaction between the pairs of attendees. Through a user interface on a computer, a user is enabled to view a graphical device that is representative of a current satisfaction of attendees of an event based on two or more factors associated with satisfaction while the event is occurring.