1. WhatsApp-like feature that lets you know when your email was read: http://mailtrack.io/
2. Create self-destructing emails with mxHero: https://chrome.google.com/webstore/detail/mxhero-for-chrome/ijhapcklhkanndjbdnhichfmolhiaekg/details
3. Get more info from the web about your contacts with Rapportive: http://rapportive.com/
4. Send links by email as fast as lightning with Send from Gmail: https://chrome.google.com/webstore/detail/send-from-gmail-by-google/pgphcomnlaojlmmcjmiddhdapjpbgeoc?hl=en
5. Watch embedded videos directly in your Gmail with Iframely: https://chrome.google.com/webstore/detail/iframely-for-gmail/bbafbcjnlgfbemjemgliogmfdlkocjmi?hl=en
actionbrainiac 