Patent ID: 7496604

Claim:
A method for reducing duplication of files in an electronic messaging system, the method comprising: receiving an electronic message addressed to a user, the electronic message including a header portion, a content portion, and a digital file; storing a representation of the electronic message with at least the header portion in association with the user's mailbox; determining a digital signature for the digital file included in the electronic message; accessing, from electronic storage, multiple digital signatures, each of the multiple digital signatures corresponding to a digital file included in a previous electronic message received by the electronic messaging system prior to receiving the electronic message; comparing the digital signature for the digital file included in the electronic message against the accessed multiple digital signatures; based on comparison results, determining whether the digital signature for the digital file included in the electronic message relates to a digital signature included in the accessed multiple digital signatures; and conditioned on determining that the digital signature for the digital file included in the electronic message relates to a digital signature included in the accessed multiple digital signatures: identifying the related digital signature, the related digital signature corresponding to the digital file; accessing volume data associated with the related digital signature, the volume data being based on a number of times that the digital file has been included in electronic messages received by the electronic messaging system; determining, based on the accessed volume data, whether the digital file has been included in electronic messages received by the electronic messaging system more than a threshold number of times; conditioned on determining that the digital file has been included in electronic messages received by the electronic messaging system more than the threshold number of times: accessing a location identifier associated with the related digital signature, the location identifier identifying a location of the shared digital file corresponding to the related digital signature, and configuring, based on the accessed location identifier, the representation of the electronic message to reference the shared digital file corresponding to the digital file; and conditioned on determining that the digital file has not been included in electronic messages received by the electronic messaging system more than the threshold number of times: storing a user version of the digital file in electronic storage associated with the electronic messaging system, and configuring the representation of the electronic message to access the user version of the digital file.