Nowadays it’s hard to believe that there was time when the most popular webmail service – Google mail, i.e. Gmail, was available to the private “invitation-only” audience. Gmail – free, advertising-supported email service is a product from Google. Users may access Gmail services on the web or via apps on Android and iOS mobile devices. As of February 2016, Gmail has 1 billion active users worldwide. It is also the first app in Google Play Store to hit 1 billion installations on Android devices. In 2014 it was reported that 60% of US mid-sized companies and 92% of US start-up companies were using Gmail.