Managing data collection for one or more scheduled alert messages. A primary or backup poller manager coordinates any number of poller services to access content and generate the alert messages. At a predefined period the poller manager is informed that an existing or new poller service is available for work. The poller manager provides a query to the poller service to access content in which one or more users have expressed an interest. Querying for a large number of users can be subdivided among the poller services. The poller service can also automatically expand the query if it yields insufficient content. The poller service generates the alert messages for the interested users and informs the poller manager when done. A change in content can be used to generate or update alert messages before their scheduled delivery. The poller manager prioritizes processing with a quality of service level.