Patent ID: 7933818

Claim:
A computer-implemented method of monitoring user browsing activity, comprising: monitoring selections made by a user during browsing of an electronic catalog of items that are available for purchase, said items arranged in the electronic catalog in item categories; concurrently with said monitoring, generating scores that represent levels of affinity the user has for at least one of: (a) specific items selected by the user in the electronic catalog, and (b) specific item categories accessed by the user in the electronic catalog, each score comprising one or more values represented in a computer memory; detecting an event in which the user discontinues browsing of an item or item category in which the user has at least a threshold level of affinity, as determined based on one or more of said scores; and determining, in response to said event and based at least partly on an output of a pseudo-random algorithm, whether to provide to the user a time-limited purchase incentive that corresponds to the item or item category, said pseudo-random algorithm inhibiting the user from predicting whether the time-limited purchase incentive will be provided; wherein the method, including monitoring the selections, generating the scores, detecting the event, and determining whether to provide the time-limited purchase incentive, is performed automatically by a system that comprises one or more computers.