1.7 kindles per subscriber per year, you mean. It's probably cleaner to work out how long it would take to recoup that 'investment' assuming subscriber readersh

1.7 kindles per subscriber per year, you mean. It's probably cleaner to work out how long it would take to recoup that 'investment' assuming subscriber readership & ad revenue don't change. He also assumes wages outside the newsroom are all in printing, which makes no sense. The article says 2 kindles over a year's costs, so his t=0.5 yr. If cutting out 4/5 of the dead tree edition doesn't do much outside raw materials, t=6yrs, which is crazy. Thing is it's all irrelevant. The assumptions & lack of information make the calculations useless. We already knew t>0, that's not a surprise.