12. A server system for searching messages, comprising: one or more processors; memory coupled to the one or more processors, the memory storing programs for execution by the one or more processors, the programs including: a receiving module for receiving a plurality of messages directed to a user, each message having a unique message identifier; a conversation module for generating a plurality of conversations, each conversation including a respective conversation identifier and unique subset of the plurality of electronic messages; a query response module for responding to a search request from a client associated with the user, the search request including one or more user-specified query terms, including: instructions for 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; instructions for transmitting over a network, for display on the client, 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 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.
12. A server system for searching messages, comprising: one or more processors; memory coupled to the one or more processors, the memory storing programs for execution by the one or more processors, the programs including: a receiving module for receiving a plurality of messages directed to a user, each message having a unique message identifier; a conversation module for generating a plurality of conversations, each conversation including a respective conversation identifier and unique subset of the plurality of electronic messages; a query response module for responding to a search request from a client associated with the user, the search request including one or more user-specified query terms, including: instructions for 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; instructions for transmitting over a network, for display on the client, 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 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. 16. The server system of claim 12 , wherein at least one of the conversations comprises a plurality of electronic messages having a close temporal relationship with each other.