Systems and methods for providing third-party content can include a data processing system receiving criteria defining online activities of an online activity type related to a product or service context from a computing device of a third-party content provider. The data processing system can identify a cluster of client devices based on the defined online activities, and determine a subset of keywords associated with the defined online activities and the identified cluster of client devices. The data processing system can determine a performance metric of the subset of keywords based on the cluster of client devices, and provide the subset of keywords and the performance metric to the computing device. The data processing system can receive from the computing device a parameter value of a first keyword of the subset of keywords to use in selecting content items of the third-party content provider associated with the first keyword.