Display the difference in time between the time you’ve spent on the page and the time the person who’s been on the page the longest has been on the page. Changes once that oldest person leaves, so eventually the time difference would be 0sec if you became the oldest person. –> place in line.
You have your own slider (like for volume — 1-100 scale) and you get a celebratory notification if your spot on the slider is the same as your partner’s spot on the slider.
A new chair icon placed at the user’s choice in a designated space for the number of people “sitting in a room with you” –> virtual copresence, dibs on your spot.
“Warmer/colder search” like Marco Polo –> color changes from red to blue shades as your position in a circle moves closer to another person’s position. Hide and seek to the mystery location of your partner.
Dense grid of “lights” like an LED grid –> clicking on a spot turns it on and off, creates a rudimentary pixelated image.
Light increases brightness/radius with the more people who join a page –> would hit max diameter before max opacity. Every person who enters the space brings their own “candle”.