Though Facebook pioneered the use of real identities on the web, Rooms is much closer to a 1990s chatroom-style community.
The service lets users join different rooms themed around interests. Users who join a room based around travel, for example, will see a feed of posts showing photos, videos or text from fellow travellers.
There is a catch however. While users can join many different rooms under different pseudonyms, they have to be invited first.
That means there is no way to search for a room on the app and, since Facebook is only currently working with a small group of "community builders", there is also no way to create a room either. That could severely limit uptake, but Rooms creator Josh Miller argued that the best communities evolve "very slowly".
One of the magical things about the early days of the web was connecting to people who you would never encounter otherwise in your daily life
Marketing understands that there are no plans to introduce ads to Rooms, since the project is in the early stages and monetisation is not a focus.
How it works
Users can invite a friend to Rooms by texting them a QR code, which is then saved to their camera roll. The next time that friend opens Rooms, the app will scan their camera roll for a code, then add them to the relevant room automatically.
As per anonymous messaging boards, such as Reddit, room creators can assign moderators, pin posts and set posting restrictions. Unlike other services however, users can adopt different names for different rooms.
The idea is similar to Facebook Groups, a mostly defunct service on the social network. But a key differentiator with Rooms is that it's better suited to mobile, plus users can adopt different nicknames for different rooms.
Rooms creator Josh Miller said: "One of the magical things about the early days of the web was connecting to people who you would never encounter otherwise in your daily life.
"Forums, message boards and chatrooms were meeting places for people who didn’t necessarily share geographies or social connections, but had something in common.
"Today, as we spend more time on our phones, primarily to communicate with friends and family, the role of the internet as a "third place" has begun to fade."
The app is only available for iOS currently.