Google has introduced a new feature in Gtalk ie., to know the past chat history of a particular buddy. There are some scenarios that we might have came across to get the chat details of particular contact for some reason. But we may need to search in gmail search box where you will end up with all the emails and other stuffs of that buddy and it will be tough time to get the info thats required.
For this we have a two alternate choice.
1. In Gmail search box type "Chat firstname.lastname@example.org" to get the chat information of that buddy.
2. Alternatively in Gtalk open the chat window of that buddy and choose the option "View Past Chats" as shown below.