Systems and methods for event detection using web-based advertisement data

Systems and methods are provided for accumulating network accessible marketplace data, determining various originating sources of the marketplace data, detecting changes in the marketplace data, and notifying users of the detected changes. The marketplace data may include advertisement data associated with advertisements on publisher web pages. The originating sources may be the publisher web pages or any of various advertising channels such as ad networks, ad services, or demand side platforms that place the advertisements on the web pages. Notifying the users may include generating a timeline and a human-readable story from the advertisement data and providing the timeline and the story to the user via a web-based interface or a notification communication such as a push notification to a device of the user.