Patent ID: 8423420

Claim:
A method comprising: hosting a virtual shopping cart associated with a user, wherein the virtual shopping cart stores items that are chosen by the user from electronic marketplaces of various merchants; tracking items acquired by the user from the various merchants, wherein the items acquired by the user are tracked through use of the virtual shopping cart associated with the user to create a transaction history in a user account of the user; receiving, from the user, a designation of an additional account of an additional user that is different from the user and is to be combined with the user account of the user; linking the additional account of the additional user to the user account of the user; combining using a computer processor the transaction history of the user account and a transaction history of the additional user account based in part on the linking to create a compiled transaction history of a set of previously acquired items; receiving an indication that the user has selected an item offered by a merchant; adding the selected item offered by the merchant to the virtual shopping cart associated with the user at least partly in response to the receiving of the indication; comparing the selected item to the set of previously acquired items in the compiled transaction history and determining that at least one previously acquired item from the set of previously acquired items is the same as the selected item or is determined to be similar to the selected item; and designating the selected item as a duplicate item in response to a determination that the at least one previously acquired item from the set of previously acquired items in the compiled transaction history is the same as the selected item or is determined to be similar to the selected item.