Long-time Gmail users most likely have tens of thousands of emails ranging from piled-up and ignored weekly newsletters to vast amounts of archived conversations with friends. There are probably hundreds of unread emails in there too that you never got a chance to sort out. Gmail Meter is a Chrome plug-in that analyses your "inbox efficiency", delivering email usage analytics and insights including the average response time to and from your contacts.

The first thing Gmail Meter does is build an inbox report including number of conversations, emails sent and received, and percentage of emails sent directly to you (rather than group mails or subscriptions). You also receive a “traffic pattern” that builds a picture of peak times for sending and receiving mail. The monthly report is useful for finding out your average response time and what day of the week you are busiest sending mails making this service an indispensable productivity tool. chrome.google.com/webstore/detail/gmail-meter/jfbklmjfigbohkochoomiljpcddghibm