8. A data processing apparatus, comprising: one or more processors; an HTTP proxy server hosted on one or more of the one or more processors; an SMTP mail transfer agent that is coupled to the HTTP proxy server; electronic mail processing logic that comprises one or more sequences of instructions which, when executed by the one or more processors, cause the one or more processors to perform the steps of: receiving an electronic mail message that comprises one or more hyperlinks; determining sender information that identifies a sender of the electronic mail message; creating and storing a record that associates the sender information with each of the one or more hyperlinks; receiving a request to access a specified hyperlink among the one or more hyperlinks; retrieving, based on the specified hyperlink, the record; retrieving, based on the sender information associated with the specified hyperlink, sender reputation information associated with the sender; determining, based on the sender reputation information, a particular action among a plurality of allowed actions; issuing a network request to access the specified hyperlink only when the particular action is allowing user access to the specified hyperlink.
8. A data processing apparatus, comprising: one or more processors; an HTTP proxy server hosted on one or more of the one or more processors; an SMTP mail transfer agent that is coupled to the HTTP proxy server; electronic mail processing logic that comprises one or more sequences of instructions which, when executed by the one or more processors, cause the one or more processors to perform the steps of: receiving an electronic mail message that comprises one or more hyperlinks; determining sender information that identifies a sender of the electronic mail message; creating and storing a record that associates the sender information with each of the one or more hyperlinks; receiving a request to access a specified hyperlink among the one or more hyperlinks; retrieving, based on the specified hyperlink, the record; retrieving, based on the sender information associated with the specified hyperlink, sender reputation information associated with the sender; determining, based on the sender reputation information, a particular action among a plurality of allowed actions; issuing a network request to access the specified hyperlink only when the particular action is allowing user access to the specified hyperlink. 12. An apparatus as recited in claim 8 , wherein the sender information comprises a network address of a sender of the electronic mail message.