Well thought out; but by "evangelize" I just meant to consider those people visiting your site who don't know what your Bingo Cards are, and to sell the concept

Well thought out; but by "evangelize" I just meant to consider those people visiting your site who don't know what your Bingo Cards are, and to sell the concept of Bingo Cards, not just your product (sell in the sense of explaining the benefits, as you did above). Like adding a link from "for instructional and entertainment purposes" to an explanation page. It would be a long-term strategy, to grow the pie, not just your slice, so it might take a long time to show up in A/B testing (and probably would be minuscule compared to the existing low hanging pie... er, fruit). So many sites assume the reader already knows what they're selling. Still, I can see that your customer acquisition costs must be much lower for those who already know, and your site speaks precisely to those people; and there seems to be enormous growth left in that segment. I mainly mentioned it because it would be a beneficial thing to do for the world - a connotation of "evangelize".