2. It's not the CEO, because they just brought back another founder, Jack Dorsey, to run the product. What kind of CEO isn't in charge of the product? Esp a company with exactly one product. Maybe if they were a diverse conglomerate you could find a way to run it without running product. But this is not a diverse company.
3. Is it Jack? Doesn't seem like it could be. If so, is he really committed to Twitter? He's only a part-time product guy, with another company he's CEO of. He probably wouldn't be a great choice for CEO either. Nice guy, but running a 350-person company with millions of users is pretty hard stuff.