Acton spoke to Forbes, outlining many minor details of what had resulted in the split with Facebook, when he and his fellow co-founder Jan Koum walked out, despite having to give up big sums to do so.
The WhatsApp founders departure was detailed by The Wall Street Journal. At that time itself, it was made clear that the overriding factor that led to the schism was because Facebook's business model revolved around selling advertising, while Acton was a strong privacy advocate.
In the Forbes interview, Acton said he had suggested a user-pays model after a certain number of messages had been sent, with perhaps a tenth of a penny being charged after a large number of free messages.
But the plan was shot down by Facebook chief operating officer Sheryl Sandberg who said it would not scale.
Facebook founder Mark Zuckerberg had decided to show targeted ads in WhatsApp's new Status feature which Acton felt broke a social compact with users.
Zuckerberg also wanted to sell business tools to allow companies to interact with users; once the companies had joined, he hoped to sell analytics tools. But the end-to-end encryption within WhatsApp would get in the way of using such tools.
When Sandberg was asked earlier this month by US politicians whether WhatsApp still used end-to-end encryption, she responded: "We are strong believers in encryption", raising doubts about the future of WhatsApp.
A WhatsApp spokesperson confirmed the placing of ads in the Status feature from next year but insisted that the end-to-end encryption feature would remain.
In August, Facebook increased the functionality of the WhatsApp Business app that it had been testing for a few months, allowing companies to send messages to customers through the app.
The Forbes feature provides plenty of background and is well worth a read.