A method, comprising: providing a computing apparatus, comprising: a transaction handler configured to process payment transactions on an electronic payment processing network; a communication portal configured to communicate with websites using communication channels independent of communications of the transaction handler; and a data warehouse; communicating, by the communication portal with a first merchant website, to allocate an offer during a session of a web browser visiting the first merchant website; storing, in the data warehouse, the offer in association with an identifier of the offer; communicating, by the communication portal, the identifier of the offer to the first merchant website to cause the first merchant website to redirect the web browser to a second merchant website, wherein the second merchant website receives the identifier of the offer from the first merchant website via the web browser during the redirecting; receiving, in the transaction handler, a first authorization request from the second merchant website for a first payment transaction, wherein the first authorization request includes the identifier of the offer; retrieving, by the transaction handler, the identifier of the offer from the first authorization request; and in response to retrieving the identifier of the offer from the first authorization request, activating, by the computing apparatus, the offer stored in the data warehouse for processing during a second authorization request from the first merchant website for a second payment transaction. providing a computing apparatus, comprising: a transaction handler configured to process payment transactions on an electronic payment processing network; a communication portal configured to communicate with websites using communication channels independent of communications of the transaction handler; and a data warehouse; a transaction handler configured to process payment transactions on an electronic payment processing network; a communication portal configured to communicate with websites using communication channels independent of communications of the transaction handler; and a data warehouse; communicating, by the communication portal with a first merchant website, to allocate an offer during a session of a web browser visiting the first merchant website; storing, in the data warehouse, the offer in association with an identifier of the offer; communicating, by the communication portal, the identifier of the offer to the first merchant website to cause the first merchant website to redirect the web browser to a second merchant website, wherein the second merchant website receives the identifier of the offer from the first merchant website via the web browser during the redirecting; receiving, in the transaction handler, a first authorization request from the second merchant website for a first payment transaction, wherein the first authorization request includes the identifier of the offer; retrieving, by the transaction handler, the identifier of the offer from the first authorization request; and in response to retrieving the identifier of the offer from the first authorization request, activating, by the computing apparatus, the offer stored in the data warehouse for processing during a second authorization request from the first merchant website for a second payment transaction.