Abstract: Methods, systems, and apparatus, including computer programs for identifying, using historical interactions associated with a first user, contact groups, where the first user is associated with each contact group, are provided. A score, with respect to a second user, is calculated for each contact group based on an amount of interaction between the second user and the respective contact group, thereby deriving a plurality of scores. A first contact group is determined. The first contact group has a first score in the plurality of scores that satisfies a predetermined threshold. A contact group suggestion is generated, responsive to the determining, that comprises an invitation to add the second user to the first contact group. The first user is notified of the contact group suggestion.

Abstract: In one aspect, the present disclosure can be embodied in a method that includes providing item recommendations for display to a user of a social networking service based on the user's responses (or lack thereof) to recommendations that were previously displayed or viewed by the user. A score is calculated for each item recommendation based on whether the item recommendation was displayed during a predetermined time period but implicitly rejected by the user. The scores assigned to the respective item recommendations are used to select additional item recommendations for display.

Abstract: Implementations of the present disclosure include generating one or more suggested social circles based on an analysis of past user interactions. The user can accept the suggested social circle and use it to distribute digital content. Generating a suggested social circle can include determining, for each of various sets of contacts, an initial score that represents a strength of the particular user's affinity to the set as a whole based on prior interactions of the particular user with the set, and determining, for each member of each set, an individual score that represents an average strength of the particular user's affinity to the member based on the interactions. An overall score for each set is calculated based on the initial score for the set and the individual scores of each member in the set. Based on the overall scores, at least one of the sets is identified for presentation as a suggested social circle to the particular user.

Abstract: Methods, systems, and apparatus, including computer programs for identifying, using historical interactions associated with a first user, contact groups, where the first user is associated with each contact group, are provided. A score, with respect to a second user, is calculated for each contact group based on an amount of interaction between the second user and the respective contact group, thereby deriving a plurality of scores. A first contact group is determined. The first contact group has a first score in the plurality of scores that satisfies a predetermined threshold. A contact group suggestion is generated, responsive to the determining, that comprises an invitation to add the second user to the first contact group. The first user is notified of the contact group suggestion.