1. A system comprising: a central processing unit (CPU); and a memory connected to the CPU and having computer-executable instructions stored therein which, when executed by the CPU, cause the CPU to execute at least: a data aggregator process configured to at least: receive a message from a wish list service each time an item is added to one of a plurality of wish lists maintained by the wish list service for users of an e-commerce site, the message being generated by the wish list service in response to the item having been added to the one of the plurality of wish lists and the message identifying the item added to the one of the plurality of wish lists, wherein the wish list service is external to the system and configured to provide wish list functionality to the users of the e-commerce site by allowing the users to add and delete items in their respective wish lists, and store the message received from the wish list service in a first queue, a maintenance process configured to move messages from the first queue to a second queue, and a network service application programming interface (API) process configured to at least: generate a stream of data from the messages in the second queue, the stream of data identifying the items added to the plurality of wish lists maintained by the wish list service, and expose the stream of data to another computing device that is external to the system through a network service API.