I will show you how to enable desktop notifications, so you will notice a new email, even if you are not in the window where you have your Gmail account open.
Sometimes we don't want others to know about our newest relationship gains or losses. This is the way your friends and other Facebook users won't even notice it when you change it.
If you don't want Google to store your chat history and the Google chat history of the person you are chatting with, you can take the chat off the record and this is how you do that.