In 19th-century novels, the word "public" meant "light" - something like the local aristocracy. A whole layer of Russian classical literature is built on the irony about this "public" - from Dostoevsky to Leskov. The audience there is something like a landowner who came to show off Voltaire's erudition in a provincial town in a circle of the same landowners who came to show off Rousseau. Having nothing against Voltaire and Rousseau, it is worth noting that this "public" lived in an environment where Voltaire was something like a Vertu phone - an object of prestigious consumption. But in fact they lived in an environment that was very divorced from Voltaire and Rousseau - frankly, a slave-master.
The moral of this excursion into the history of the concept is this: not everything that is called the public is the public. It so happened that I recently found myself at the anniversary of a good radio station. The event is public. I'll omit the details, but in general it's a big stage, where listeners' favorite radio hosts joke from the podium into loud microphones into a large hall. Then - loud music (good), and then music that encourages dancing? While all this was unfolding, I hung around the bar with one of the most literate economists in the country, trying to discuss the topic of Sergei Guriev. Everything would be fine, but the music sounded painfully loud - and encouraged to dance. They explained with gestures, and with that they dispersed - to their tables. Public event? No.
What is public space and public? This is not a place where music plays, or cyclists pedal, or hipster-looking youth walks peacefully. A public space is a place where citizens can have a conversation and exchange arguments. Everything else is any kind of space, but not public. If you find yourself in a place - and almost all places, for example, in Moscow, are like that - where music is played loudly or people speak from the podium (from the screen) into microphones, then this is not a public space. Maybe communal, maybe ideological, maybe some kind of public place. But not public. Public - this is where you can, talking for a long time, discuss all the details of a public issue (res publica).
Therefore, almost everything that is TV is not public.
Therefore, almost everything that is radio is not public.
Therefore, everything that only imitates discussion is not public.
Public - it is where everyone can calmly pronounce their reasonable arguments and respond to the arguments of the interlocutor. Reasonable arguments, by the way, are not pronounced quickly and without hesitation. They are reasonable because they are formulated for a long time and pronounced in a tongue-tied tongue - a lively language is only in the market, and even on TV and on the radio. Therefore, an Internet forum is almost always also non-public.
The audience is where people listened to the arguments, weighed them and formulated their opinion. If the opinion goes straight to the brain (now the visual screen is the best way to do this), then the audience cannot arise. At best, if we compare with the Middle Ages with a stretch, these are the peasants in the church, directly perceiving - in the form of the iconography surrounding them - the whole picture of the world at once.
The public and the public have undergone unprecedented erosion by modern media - screens (first television) played a decisive role in this. But publicity and the public still flicker here and there: at boring seminars in stuffy auditoriums or in suburban spaces where city dwellers, ignoring leisure, go for the weekend to exchange arguments. The last, by the way, is a direct reproduction of the practices of the Renaissance, when humanists preferred the solitude of the Florentine Academy to the noise of cities. But these are all external attributes. If a city dweller needs to identify the public and the public space, then he will find all this easily: there people can carry on an unhurried exchange of arguments - slowly, in each other's faces and without being disturbed by extraneous noise. Even if you want to dance to it.