I’m not downvoting, but I think the concept of anonymous speech goes way way back to the origins of writing, doesn’t it? The change in recent years is that it’s extra hard to stay anonymous, what with the surveillance economy?
1. The cost of printing/transcribing something
2. Literacy rates
3. Constraints tied to physical distribution
...the reach of that potentially "anonymous speech" was the tiniest fraction of what we experience today. And even then it wasn't necessarily anonymous, unless you just left books lying around?
I won't argue that it wasn't possible. But that link shows 20-40 books, and covers 3000 years of human culture. That's about one anonymous book per century. I think we need more anonymity than that. But I think the amount of anonymity we have now is disastrous to civil society.
Well, with a rumor, the original source is obscured. So in a sense they are getting their info out there anonymously (to all but the first-hand confidantes).