Abstract: A method of determining the effectiveness of marketing content comprising the steps of recording user access to items of marketing content. Recording customer transactions, and for each transaction, identifying previous access to items of marketing content by the same customer. Assigning a value to each of the identified accessed items of marketing content, the assigned value being derived from the value of the transaction. Then combining the values assigned to each accessed item of marketing content by the different transactions to provide a customer score for that item, and deriving a performance score for each item of marketing content from the customer score for that item and the recorded user access for that item.