Abstract: Techniques for electronic messaging including receiving, at a computer system, a first request to send, on behalf of a first user, a user-indicated attachment to a recipient body with a first message, identifying an attachment transmission rule setting corresponding to either the first user or a second user corresponding to the recipient body, determining whether the identified attachment transmission rule setting is satisfied by the first user, the user-indicated attachment, the first recipient body, and/or the second user, and either automatically causing a first transmission of the user-indicated attachment to or from the computer system in response to the determination indicating that the attachment transmission rule setting is satisfied, or automatically avoiding the first transmission of the user-indicated attachment to or from the computer system in response to the determination indicating that the attachment transmission rule setting is not satisfied.

Abstract: Techniques for electronic messaging including transmitting or receiving at a first time a first message associated with a first attachment, transmitting or receiving at a second time a second message associated with a second attachment, obtaining first and second values of a property at about the first and second times, in which the property is a descriptive property of an attachment or the property is an operating context property of the message processing system, transmitting or receiving the first attachment in association with the first message based on a determination whether the first value satisfies a condition, determining whether the second value satisfies the condition, and transmitting or receiving a fingerprint for the second attachment in association with the second message based on whether the second value satisfies the condition, in which only one of the first and second values satisfies the condition.

Abstract: Techniques for electronic messaging including identifying a first user-indicated attachment associated with a message to a recipient body, and determining that the first user-indicated attachment is redundant, such that a fingerprint for the first user-indicated attachment corresponds to a second user-indicated attachment. In some examples, the determination results in a sending device presenting a notification that the first user-indicated attachment is redundant with an attachment previously sent to or sent by a recipient user. In some examples, the determination results in a recipient device presenting a description of the message that includes an indication that the first user-indicated attachment is redundant and selectively enabling a user-initiated operation related to presentation of the message. In some examples, the determination results in transmitting to an end-user device an indication that the first user-indicated attachment is redundant.

Abstract: Techniques for electronic messaging including receiving a first request to send a first attachment to a first recipient body with a first message, receiving a second request from an end-user device to send a second attachment to a second recipient body with a second message, obtaining a first fingerprint for the second attachment, determining that the first fingerprint matches a second fingerprint for the first attachment, determining, based on the first fingerprint matching the second fingerprint, that the end-user device does not need to provide the second attachment, and indicating to the end-user device, in response to the determination that the second end-user device does not need to provide the second attachment, that the end-user device does not need to transmit the second message attachment to another device in association with the second message.