Gmail is a great invention, though I prefer to tag my mails in del.icio.us. If the link's private I know I haven't replied to it, and after the reply I delete the link.
Some days I wonder why I have accounts for near to all IM services when I never use them. I never got into the habit of real time conversations via the internet. I'm probably too old-fashioned to chat; it's too much like using a telephone, which makes it sort of impractical to use for detailed conversations.