Patent ID: 8583747

Claim:
A method comprising: at a conversation-based messaging system having one or more processors and memory storing one or more programs executed by the one or more processors: storing plurality of conversations, each of the conversations having a respective conversation identifier and comprising one or more messages sharing a common set of characteristics that meet predefined criteria; storing a plurality of labels, including a first label associated with messages from multiple conversations of the plurality of conversations and a second label associated with messages from multiple conversations of the plurality of conversations; selecting a conversation from a plurality of conversations, the selected conversation having a plurality of messages associated with the first label; in response to an action specifying that the second label is to be associated with the selected conversation, associating the second label with every message in the selected conversation, such that the plurality of messages in the selected conversation are each associated with both the first and second labels; accessing an index of the conversations that includes an index entry for the first label and an index entry for the second label, wherein the index enables the messaging system to identify messages including a respective label in response to a search query that includes a representation of the respective label; modifying the index entry for the second label to account for the association of the second label with the messages in the selected conversation; receiving a respective search query including a plurality of search terms, the plurality of search terms including a search term corresponding to the first label and a search term corresponding to the second label; and in response to receiving the respective search query, applying the respective search query to the index of the conversations to identify a set of search results including one or more messages of the selected conversation with which the first label and the second label have been associated.