Method and apparatus to detect fraudulent activities within a network-based auction facility

The method of claim I, wherein the at least one of the plurality of triggering events is a sales transaction event, the method further comprising prohibiting a completion of the sales transaction event responsive to the detection of the lack of correspondence between the first identifier and the second identifier.

The method of claim I, wherein the at least one of the plurality of triggering events is a sates transaction event, the sales transaction event including at least one of registering with the network-based transaction facility, communicating an offer to sell an offering via the network-based transaction facility, communicating and offering to purchase the offering via the network-based transaction facility, communicating a feedback regarding a transaction, or updating a profile maintained by the network-based transaction facility.

A system to detect a fraudulent activity at a e network-based transaction facility, the system comprising:

• an identifier processor to generate and forward a shill cookie over a network to be stored on a client machine responsive to at least a first of a plurality of triggering events being produced at the client machine after the client machine accesses the network-based transaction facility via the network , the shill cookie to contain information related to a first identifier associated with a first user identity, the identifier processor further to generate a second identifier associated with a second user identity, the second user identity to be stored in the shill cookie on the client machine, the second identifier being generated responsive to at least a second of the plurality of triggering events with respect to the network-based transaction facility;
• and
• a detection processor to detect a potentially fraudulent activity by detecting a lack of correspondence between the first identifier and the second identifier.