Back in 2017, Facebook rolled out the “Find Wi-Fi” feature globally, a feature that lists the nearby Wi-Fi networks that Page owners shared with Facebook. Two years later, Facebook is working to expand this feature from being a list of nearby Wi-Fi networks to a service that manages the Wi-Fi connections on the device.

I came across this unreleased feature by looking into the code underneath Facebook for Android.

This feature shows up as an additional section in the “Find Wi-Fi” part of the Facebook app. To opt-in, press the “TURN ON” button in the banner, in which the banner states “Let Facebook help you find and connect to fast, reliable networks nearby by managing Wi-Fi on your device.”

In the onboarding process, Facebook will list the on-device saved Wi-Fi networks and let users pick their preferred networks by tapping the star icons next to each saved network list item.

If the current Wi-Fi connection is considered undesirable, users are given options to send network feedback: “Connection is too slow”, “Network isn’t secure” and/or “Connection drops off”.

For now, with this feature turned on, the app will periodically send your geolocation to Facebook’s server to get a list of nearby recommended networks.

I have been observing the development of this feature since February 2019. Coincidentally, I came across an endpoint in Facebook’s server which belonged to the same project. The endpoint returned a huge list of publicly-accessible Wi-Fi networks. It returned approximately 13000 networks in Manhattan, NY.

The returned data includes the name of each Wi-Fi network, the signal strength and the approximate coordinate of each network. After I tweeted about my discovery of this list of Wi-Fi networks, Facebook quickly blocked my access to this endpoint. The endpoint has since been returning an empty list.

Interestingly, judging by the network names, it seemed most of these 13k Wi-Fi networks in Manhattan are residential and not belong to businesses. It is unsure how Facebook obtained this huge list of what appears to be residential Wi-Fi networks. But it would not be surprising if Facebook “crowd-sourced” the data from app users who granted Location access.

At least on Android, it is possible for apps to periodically scan the nearby Wi-Fi networks in the background and send it to servers. This functionality is often seemed important for companies that monetize data for advertisements -- by crowd-sourcing Wi-Fi networks and associate them with geolocation data, companies can determine relations between users, for example, whether they are roommates, neighbors, colleagues, where they work, etc. This allows targetting ads more precisely.

While looking at the bright side, this could make the life of users who rely on public Wi-Fi networks easier. However, with this amount of scrutiny, I am sure Facebook will ensure their data handling to be proper, including restricting this feature from connecting devices to residential Wi-Fi networks without permission.

Similarly, Google introduced Google Connectivity Services back in 2015 and it also manages Wi-Fi connections to open public Wi-Fi networks.

The time it takes to develop and release experimental features like this varies. Sometimes, public receptions could sway the fate whether features will eventaully be released to the public.