Abstract: Disclosed is an ad server and local device that interface for selecting advertisements to be viewed by users of an online service based upon user activity. The local device preferably stores a targeted activity list of activity identifiers and associated advertisements in memory, preferably in cache memory. The local device monitors the activity on the local device and compares the activity to the identifiers in the targeted activity list. If the activity matches one of the identifiers, the local device causes one or more advertisements to be played.