"Seen by" Facebook featureFacebook is gradually rolling out a new feature that displays who’s seen a post, and it has some serious online privacy–not to mention social awkwardness–implications. Posts will now show “seen by” underneath them, followed by a list of the people who have viewed them. The “seen by” feature shows up under each individual reply in a thread, not only the main content (for example, if someone sends you a Facebook invite to a party, they’ll be able to see whether you clicked open the invitation and whether you read individual replies on the event page).

It’s enabled for groups, which can include which can include private messages sent to more than one person, content shared in public and private groups, and event invitations, and it appears in both mobile and web-based versions of the site.

Hover your mouse over the “seen by” text and you’ll get a list of the full names of the people who saw it, like this:

"Seen by" Facebook feature

Or click on the “seen by” text to get a pop-up window with all those people’s profiles:

"Seen by" Facebook feature

You can imagine the awkward social situations this feature can lead to: you open a Facebook message at work, see a lot of text, and close it to reply when you have more time later. Will the friend who sent it think you’re ignoring him or her? Or you get an event invitation but aren’t sure whether you’re free on that day, so you don’t RSVP yet: whoever sent you the invite—and everyone else who’s invited—can see that you saw it and didn’t reply. The “seen by” feature puts social pressure on people to reply to posts immediately or risk looking rude.

Unfortunately, there’s nothing you can do to stop people from seeing that you’ve viewed a post. When asked if they planned to change this or add it to your home feed, Facebook said they were “not going to discuss what we might (or might not) do in the future.” Your only option is to avoid using any group discussion features on Facebook, whether they’re private messages between a few people, discussions under an event invitation, or anything similar. Stick to email, Evite, or any other website that you trust.