1. A method for building an interest profile for a user comprising: performing the following steps using one or more processors: maintaining an interest profile for a user; capturing an outgoing document being sent by the user; determining an electronic message thread comprising the outgoing document and one or more documents related to the outgoing document which are part of the same conversation as the outgoing document, wherein the one or more documents related to the outgoing document include at least some terms or content not present in the outgoing document, and wherein the one or more documents of the message thread includes a stored incoming document; scanning the message thread for at least one of terms or content to determine at least one item of interest for the user based on the at least one of terms or content of the scanned message thread, wherein one or more terms and content of the stored incoming document and of the outgoing document are weighted differently when determining the at least one item of interest; and updating said at least one item of interest of the interest profile.