There are many products that have hundreds of millions of active users in a single month, but there are few that have passed the billion mark. However, the select group, which includes the likes of YouTube and Facebook, has just gotten bigger.
And it is Google and Facebook which once again add new members to that list, with Gmail and WhatsApp, respectively, joining the pack. Both services passed that milestone in January, with one taking longer than the other to reach it.
Gmail was first introduced nearly 12 years ago, on 1 April 2004. The email service was initially available only via invites, becoming available to a wider audience nearly three years later. Gmail had one of the longest beta testing phases, which lasted until mid-2009. It reached 900 million users in May 2015, just over 11 years after its soft launch.
WhatApp, meanwhile, has evolved much more quickly. Its initial release dates back to January 2010, six years ago. In mid-April, CEO Jan Koum announced that the service had 800 million monthly active users. At the time, WhatsApp was about six months into Facebook ownership.
Fast forward to today and both services now claim to have more than one billion monthly active users. But, are those figures close to the truth? In WhatsApp's case, users are directly linked to phone numbers, and you cannot have more than one account per phone number.
Users can be counted twice if they have two phone numbers, but, realistically speaking, more than two sounds a bit far fetched. Not to mention that it makes little sense to have multiple WhatsApp accounts, since you would normally be chatting only with your phone contacts anyway, because that is the way the service is designed to be used.
In Gmail's case, however, it is not uncommon for one user to have more than one account. At some point I had two (possibly more, but I cannot recall exactly), but my colleague Wayne Williams says he now has five.
I know other Gmail users who have a similar number of accounts, so I wonder how exactly does Google - or WhatsApp for that matter - know exactly how many actual users are accessing their service every single month?