Gmail just hit a major milestone by Benjamin Snyder @FortuneMagazine May 29, 2015, 2:23 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Google’s Gmail, already the most popular email service around, just notched member No. 900 million, the company announced at its annual I/O developers conference this week. Gmail doubled its number of users in the last three years, USA Today reports. The announcement was made by Sundar Pichai, Google’s senior vice president of products. The news comes as Google is publicly launching Inbox, a version of Gmail designed for mobile phones. Over three-quarters of Gmail users log into their email accounts from their phones. Google’s Pichai recently spoke with Fortune’s Adam Lashinsky about the company’s business strategy and being patient.