Why did I get a note about 'IM history in Gmail'?
Gmail now offers users the option to sign in to their AOL Instant Messenger (AIM) account so they can chat with their AIM buddies in Gmail. This message simply means that the person you're chatting with uses AIM in Gmail and is using the chat-history feature. Chat history allows Gmail users to store the text of their chats, so they can easily search for those chats later. If you'd prefer your friend not to save your conversations, you can always ask your friend to go "off the record". Going off the record will turn off their chat history.