Thanks for sharing your thoughts, Smillew.
I do take into account that there's a level of uncertainty in how much you get paid from any specific member reading your article.
As I say in the article, this could explain variations in daily payments per minutes when there are few readers in a given day.
In days where there are dozens of readers or more, however, it's unlikely very many of them will be outliers in terms of how many articles they read per month.
That's why I'm fairly confident that the average payment per member reading minute grows exponentially for "viral" articles.
In fact, I think that makes sense from a business perspective. Viral content makes the site more compelling, and has a higher chance of bringing in new subscribers.
Having said all that, as I recall also saying in the article, Medium can and probably will continue changing their compensation model for writers, and the recent addition of affiliate payments for bringing in new subscribers may make them change this escalating payment formula.