Abstract: An online system tracks stores information identifying content provided by third party systems and accessed by online system users as well as interactions with advertisements performed by online system users. When the online system identifies an opportunity to present an advertisement to a viewing user, the online system identifies content from third party systems accessed by the viewing user and content from third party systems accessed by additional online system users who interacted with advertisements. A score is computed for various advertisements based at least in part on correlations between content from third party systems accessed by the viewing user and content from third party systems accessed by additional online system users who interacted with advertisements. The online system selects candidate advertisements to evaluate for presentation to the viewing user based on the scores.

Abstract: In one embodiment, a computing system accesses a tracking record of a real-world object during a first movement session. The first tracking record comprises a plurality of locations of the real-world object relative to a first user. The system determines a display position of a virtual object representing the real-world object on a display screen of the second user based on the tracking record of the real-world object and the current location of the second user. Based on the determined position of the virtual object on the display screen, the system displays the virtual object on the display screen.

Abstract: In one embodiment, a computing system accesses a tracking record of a real-world object during a first movement session. The first tracking record comprises a plurality of locations of the real-world object relative to a first user. The system determines a display position of a virtual object representing the real-world object on a display screen of the second user based on the tracking record of the real-world object and the current location of the second user. Based on the determined position of the virtual object on the display screen, the system displays the virtual object on the display screen.

Abstract: In one embodiment, a computing system accesses a first tracking record of a first user during a first movement session. The first tracking record comprises a plurality of locations of the first user and associated time measurements. During a second movement session, the system determines a current location of a second user and an associated current time measurement. From the plurality of locations in the first tracking record, a first location of the first user in the first movement session is determined based on (1) the associated time measurement relative to a start time of the first movement session and (2) the current time measurement relative to a start time of the second movement session. The system determines a display position of a virtual object on a display screen of the second user based on the first location relative to the current location of the second user.

Abstract: An online system tracks stores information identifying content provided by third party systems and accessed by online system users as well as interactions with advertisements performed by online system users. When the online system identifies an opportunity to present an advertisement to a viewing user, the online system identifies content from third party systems accessed by the viewing user and content from third party systems accessed by additional online system users who interacted with advertisements. A score is computed for various advertisements based at least in part on correlations between content from third party systems accessed by the viewing user and content from third party systems accessed by additional online system users who interacted with advertisements. The online system selects candidate advertisements to evaluate for presentation to the viewing user based on the scores.