Red Bubbles
We watch as Mae receives hundreds of thousands of replies to her 24/7 posting of her life through red text bubbles on-screen. These are symbolic of the love we seek from the world (hence the red color) as well as the dangers created by the need to be loved (the anxiety created from not getting messaged, or the hatred that can spew into someone's social media thread).
24/7
Mae opens up her life to the public so they can see every second of her life. But whatever she sees so does her followers. This is unfortunate for anyone who doesn't want to be on-camera, for example her parents during a private sex act. This is a symbol of the very real encroachment on others privacy that people have with social media.
Double Standard
Bailey has Mae be the first to wear the 24/7 video monitor that links her to social media at all times. But he doesn't wear one himself. This is a symbol of the double standard many executives set as Bailey preaches transparency while not being willing to open his life up 24/7 to the people.
Facade
Annie is able to help Mae get a job at The Circle where she's one of the higher ups. Annie's perky, vibrant and totally believes in The Circle. But this is a symbol of a facade she puts on to make others believe all is well, when in reality she is addicted to prescription drugs to keep her awake. She overworked, and with deadlines and target numbers to reach she's stressed to the max.
Mercer
Mercer loses his life when drones engage him while he's driving across a bridge to get away from Mae's followers. His crash into a ravine is a symbol of the potential horror that can be inflicted upon others if we don't have boundaries with social media. This includes bullying, shaming and physical violence that can have the potential to head towards life-threatening circumstances being created through someone's online presence.
