Meta is adding an “activity status” to Threads so that you can see who’s actively online as you’re scrolling your feed. In a post, Threads boss Adam Mosseri pitches it as a “way to help you find others to engage with in real-time.” The activity status will show up next to your profile picture in the feed and on your profile, based on screenshots Mosseri shared.
Fortunately, if you don’t want people to know when you’re online, you don’t have to share that. “Only people who have activity status turned on will be able to see when you’re online, and you can turn this off within your settings at any time,” Mosseri says.
I can’t currently find how to turn on the feature. It might be user error, but I’m guessing it just hasn’t rolled out to me yet. Even when I get it, I’ll probably be keeping it off.