Abstract: A notification system and method for providing a notification of comparison data for products or services to users for display on a user's computer. User notification data is stored for each of a plurality of users, user notification data comprising user data related to a user, type data identifying at least one type of product or service of a interest to the user, parameter date comprising parameters required for the comparison of data products or services of a product or service type of interest to the user, and temporal data indicative of when the user requires a notification. The user notification data is read to determine when to determine product or service comparison data by sending a query based on the type data and the parameter data to at least one product or service data source. Notification data is generated for display on a user's computer. The notification data includes the comparison data and a selectable link for each product or service compared in the comparison data.