Her assumption that one out of four GMail ads gets clicked on seems wildly off-base; I thought that these days, a click-through rate of one percent is considere

Her assumption that one out of four GMail ads gets clicked on seems wildly off-base; I thought that these days, a click-through rate of one percent is considered a smashing success. But of course if you know that every GMail page has four ads, and you assume that one quarter of the ads gets clicked on, the math for the rest of the problem gets a lot easier.