1. A method comprising: detecting a request to append a signature to an outgoing email, wherein the email is addressed from a sender to a recipient; determining one or more temporal conditions associated with the email; determining one or more social relationships associated with the recipient; selecting the signature from a predefined list of signatures, wherein the selecting includes comparing a group of signature rules to the one or more temporal conditions and the one or more social relationships; appending the signature to the outgoing email; and transmitting the email to the recipient.