Tor: It’s not just for drugs anymore. One million people used the privacy service to access Facebook in 30 days, the highest number since Facebook started offering Tor access to its service at facebookcorewwwi.onion and on Android devices.

“In June 2015, over a typical 30-day period, about 525,000 people would access Facebook over Tor,” said an announcement from Facebook engineer Alec Muffett, who helped built Facebook’s Tor compatibility. “This number has grown – roughly linearly – and this month, for the first time, we saw this ’30-day’ figure exceed 1 million people.”

Tor is a service that lets users browse the Web anonymously, or at the very least with an obscured IP. The protocol works by routing users’ traffic through “nodes,” computers offered by volunteers as access points for traffic. Traffic is routed through three nodes, and encrypted every step of the way, meaning no single node could possibly decrypt the traffic.

Try to access facebookcorewwwi.onion on a standard browser and you’ll see only an error message. This is because using Tor requires a Tor-compatable browser, the best known of which is (unsurprisingly) called Tor. If you’ve used Firefox before, the interface will be familiar, but there are a number of built-in security features.

It may seem strange to use Facebook, a service built around users’ real-world identity, on Tor, a service built on the concept of anonymity. Facebook sees this simply as an added layer of security, a way to access the site with protection, as well as a usability feature for enthusiastic Tor users.

One million users in a month represents a tiny fraction of Facebook’s 1.59 billion monthly users, but that kind of user base means even a tiny fraction adds up to a lot. Whatever you think of Facebook, a huge number of people wanted to access the site through Tor.