If memory serves Evan Williams had to fire everyone including himself in the process of getting Blogger to the break-even point; a point that it reached only a few months prior to it's sale to Google. He seems like a resilient guy but it doesn't seem like he has any exceptional ability to generate profits. I don't know Jack Dorsey's back story so I can't comment there. Can you explain your thinking?

One success could mean you got lucky, more than one is meaningful. Blogger is Evan Williams' only business success; if Twitter actually makes enough money to justify the amount of money invested, that would be meaningful.

I think it's too early to pass any judgment on Square.