1. A computer-implemented method to guide purchasing via a user device, comprising: receiving, at one or more computing devices, first information indicating that a user device has presented online content related to a given product to a user of the user device; providing, to the user device and in response to receiving the first information, second information to cause the user device to display a control for the user to indicate an interest in purchasing the given product; receiving, by the one or more computing devices and from the user device, an indication that the user of the user device has indicated an intent to purchase the given product through user interaction with the control; determining, by the one or more computing devices, at least one sequence of tasks required to purchase each of a plurality of products; associating, by the one or more computing devices, the intent to purchase the given product with a determined sequence of tasks required to purchase one of the products in the plurality of products, wherein the associated sequence includes: (i) a task for choosing a product type, (ii) a task for choosing one or more product features, (iii) a task for choosing a product model, and (iv) a task for choosing a merchant; determining an order for the tasks within the associated sequence of tasks based at least in part on information gathered from consumers who have previously performed some or all of the tasks in the associated sequence of tasks; determining, by the one or more computing devices, a current state of the user device in the associated sequence of tasks; and presenting, by the one or more computing devices via the user device, a next uncompleted task according to the determined order for the tasks from the associated sequence of tasks based on the user device's current state in the associated sequence of tasks.