System and Method for Targeting Advertisements or Other Information Based on Recently Sent Message or Messages

A method of serving information items in association with one or more messages sent by a client includes identifying at least one message sent by a client, obtaining at least one information item associated with the at least one identified message, and preparing for display to the client the at least one information item. The method may include identifying one or more categories associated with the message, or identifying one or more elements in the message that correspond to predefined information entity types. The operation of associating one or more categories with a message may be done before, in parallel, or after sending the messages as an outgoing message.