5. A method for displaying messages, comprising: at a server having one or more processors and memory storing programs executed by the one or more processors: receiving a plurality of messages directed to a user, each message having a unique message identifier; generating a plurality of conversations, each conversation including a respective conversation identifier and unique subset of the plurality of electronic messages; and responding to a search request from a client associated with the user, the search request including one or more user-specified query terms, including: selecting a list of conversations from the plurality of conversations in accordance with the search request, each conversation in the list including at least one electronic message that matches the search request, at least one conversation in the list comprising two or more electronic messages; and transmitting over a network to the client for display the list of conversations in an order determined in accordance with first predefined criteria, each conversation in the list being represented as a single item in the list of conversations, at least one of the conversations in the list comprising two or more electronic messages, wherein each item representing a conversation having a plurality of messages has an associated icon indicating the number of electronic messages in the conversation.
8. The method of claim 5 , wherein the single item for a respective conversation in the list is generated so as to include a text string having a highlighted instance of at least one of the one or more user-specified query terms.