Get More From Gmail with Five Little-Known Features

Gmail Associate Product Marketing Manager Bill Kee lists five cool Gmail features you probably didn't know existed, including "reply by chat":

Most people know that you can chat with your contacts in Gmail if they're using Gmail too. But there are some subtle features that make chat particularly useful in the context of using your email, like replying by chat. If you've received an email and notice that the sender is online (by seeing the little green dot next to his or her name in the conversation), you can click the button "reply by chat." What's particularly convenient about this is that the chat will be archived as part of the email thread to which you replied. I like this most because it means when I search for anything related to that thread, I find the chat transcript alongside all the relevant email messages.