You use email in your applications, right? Ok, that’s a rhetorical question. Of course you do. Despite email being over 30 years old, it’s still the most popular application on the planet, by far. Here are some stats from Pingdom, for 2012: 2.2 billion – Number of email users worldwide 144 billion – Total email traffic per day worldwide 4.3 billion – Number of email clients worldwide in 2012 Stagg