Particular embodiments detect events associated with information about events and activities that a user has engaged in. The events may be of a particular type. An entity associated with an event may request that the user provide further information on the event and, based on the received information, the social-networking system sends the user a request for follow-up information after an appropriate time delay. The time delay may vary based on the user activity and the type or context of the event that triggered the request. After the follow-up information is received, such information is stored in the social-networking system and may be used to determine recommendations, sponsored stories, advertisements, etc. to send to friends of the user. The information may also be used for ranking or filtering recommendations.