No one here is in some secret market that no one knows about. If you have no competitors, you're either a government sanctioned monopoly or in the wrong market.
That's definitely false.... there are thousands of niche markets with 1-5 competitors where each can make 5 figures per month. Why invite more competition?
Also, it's not like you email your competitors and exchange revenue numbers.
I agree you shouldn't share the URL, someone could easily copy the startup or model. What I don't agree with is that someone would be able to execute it properly.
I seriously don't understand this trend of people blabbing their revenue numbers and showing their exact website... there is no better way to create a competitor than that. And for what, an ego boost?