Perhaps "throw away" is the wrong phrasing. The aggregates are always averages, no absolute counts. After a rollup, the maximum of some value will no longer be the maximum - it'll be the average of a bunch of maximums. There's no type information with which one can maintain this, and no observation/sum counting. For 'data whore' people like you and I, this should matter. :) (or at least, it does to me)

The article seems to be about trying to get an approximation of observation count data out of Graphite, which doesn't really store that.