Not surprisingly, Signal has been staggering under the load of refugees from WhatsApp following Facebook’s ultimatum about sharing their data with other companies in its group. According to data from Sensor Tower Signal was downloaded 8.8m times worldwide in the week after the WhatsApp changes were first announced on January 4. Compare that with 246,000 downloads the week before and you get some idea of the step-change. I guess the tweet — “Use Signal” — from Elon Musk on January 7 probably also added a spike.

In contrast, WhatsApp downloads during the period showed the reverse pattern — 9.7m downloads in the week after the announcement, compared with 11.3m before, a 14 per cent decrease.

This isn’t a crisis for Facebook — yet. But it’s a more serious challenge than the June 2020 advertising boycott. Evidence that Zuckerberg & Co are taking it seriously comes from announcements that Facebook has cancelled the February 8 deadline in its ultimatum to users. It now says that it will instead “go to people gradually to review the policy at their own pace before new business options are available on May 15.” Ho, ho.

Signal is a very interesting outfit, incidentally, and not just because of its technology. It’s a not-for-profit organisation, for one thing. Its software is open source — which means it can be independently assessed. And it’s been created by interesting people. Brian Acton, for example, is one of the two co-founders of WhatsApp, which Facebook bought in 2014 for $19B. He pumped $50m of that into Signal, and no doubt there’s a lot more where that came from. And Moxie Marlinspike, the CEO, is not only a cryptographer but also a hacker, a shipwright, and a licensed mariner. The New Yorker had a nice profile of him a while back.