David and Christopher start the show by discussing a technology that drove decades of innovation: the spreadsheet. Dan Bricklin, creator of VisiCalc - the Lotus and Excel predecessor that was so successful people bought Apple computers just to use it - joins to talk about why number-crunching was such a killer app. Then WSJ reporter Julia Carpenter comes on to talk about family cellphone plans - how they came to be the most popular plans, and why even non-families use them. Finally, David interviews Troy Hunt, creator of Have I Been Pwned, about whether your data is secure (probably not) and what you can do about it (plenty).