But there are no structural barriers to being watched or heard online. In fact, exactly the opposite is the case. For the ultimate in public spaces, there's Usenet. Usenet is a distributed collection of tens of thousands of discussion areas devoted to everything in the world you might want to talk about. It's been around for a few decades, and was already well-established when I first got an Internet account in 1988.
Nobody controls it, nobody owns it, and nobody can censor it.
According to the most recent statistics from yesterday, the average number of individual messages people post each day is 791,377. That amounts to 46,800 megabytes a day. To put this into more realistic terms, most of the folks in the audience have seen the size of books with the complete works of Shakespare. Usenet messages, if printed out, would fill about 5,200 of these books. People feel comfortable engaging in public discourse online if they can do so without their privacy being violated.