Johari window
Overview
The Johari window is a model of self-awareness devised in 1955 by Joseph Luft and Harrington Ingham. The name "Johari" combines their two names. It sorts information about yourself into 4 areas along 2 axes: "whether you know it" and "whether others know it."
The open area is what both you and others know, the blind spot is what others know but you don't, the hidden area is what you know but others don't, and the unknown area is what neither you nor others know. Self-disclosure turns the hidden area into the open area, and feedback from others turns the blind spot into the open area.
Question boxes and the Johari window
A question box works as a device that moves the Johari window. When a sender says "My first impression of you was X," the blind spot of the person answering opens up. When the person answering reveals in an answer their true feelings that they don't normally talk about, the hidden area turns into the open area.
Some feedback can be given because the sender is anonymous. "It's hard to say under my real name, but I love how X you are." "Your recent posts look a bit aggressive." Frank feedback like this can light up the blind spot of the person answering.
Not opening the window too wide
In Johari window theory, the bigger the open area, the better your relationships are said to be. But in the context of a question box, this doesn't apply without conditions.
Self-disclosure has a sensible range. Laying everything bare in a question box is close to oversharing. A pace that feels comfortable to you is a good guide for how fast to widen the open area. A question box is not a place that forces self-disclosure, but a place where you can adjust the size of each area at your own pace. Choosing "not to answer" is also a way to protect the hidden area.