9. A computer system for locating information on a topic within a peer-to-peer network, the computer system comprising: one or more processors; one or more non-transitory computer-readable storage media; program instructions stored on the one or more non-transitory computer-readable storage media for execution by at least one of the one or more processors, the program instructions comprising: program instructions to receive, on a first peer computer within the peer-to-peer network, a request to locate a topic; program instructions to determine a second peer computer within the peer-to-peer network to query for the topic; program instructions to query an index of the second peer computer for the topic; responsive to determining the topic exists in the index of the second peer computer, program instructions to receive identification information of participants of an instant messaging conversation corresponding to the topic; program instructions to determine the received identification information originated from a currently unavailable peer computer, wherein the currently unavailable peer computer previously pushed an index with the identification information to the second peer computer; and program instructions to store, on the first peer computer, the identification information of the participants and indexing the stored identification information by the topic.
9. A computer system for locating information on a topic within a peer-to-peer network, the computer system comprising: one or more processors; one or more non-transitory computer-readable storage media; program instructions stored on the one or more non-transitory computer-readable storage media for execution by at least one of the one or more processors, the program instructions comprising: program instructions to receive, on a first peer computer within the peer-to-peer network, a request to locate a topic; program instructions to determine a second peer computer within the peer-to-peer network to query for the topic; program instructions to query an index of the second peer computer for the topic; responsive to determining the topic exists in the index of the second peer computer, program instructions to receive identification information of participants of an instant messaging conversation corresponding to the topic; program instructions to determine the received identification information originated from a currently unavailable peer computer, wherein the currently unavailable peer computer previously pushed an index with the identification information to the second peer computer; and program instructions to store, on the first peer computer, the identification information of the participants and indexing the stored identification information by the topic. 15. The computer system of claim 9 , wherein said determining the second peer computer to query for the topic, comprise program instructions, stored on the one or more non-transitory computer-readable storage media, to identify a user name in a contact list of an instant messaging program operating on the first peer computer, wherein the second peer computer corresponds to the user name.