1. A method comprising: receiving an image as a search query from a first user, the image being a first event; identifying search parameters in the search query that include first event attributes associated with the first event; identifying from a first activity stream, for the first user in a social network, the first event and the first event attributes for the first event; identifying from a second activity stream, for a second user in the social network, a second event and second event attributes for the second event, the second event attributes including data describing the second event; identifying contextual information describing a relatedness of the first and second users based on the first and second event attributes; associating the first event and the second event as being part of a single activity based on the contextual information describing the relatedness of the first and second users; generating a first task associated with completing the activity for the first user; generating a second task associated with completing the activity for the second user; and updating the activity based on a status change of at least one of the first and second tasks.