The online apps concentration of revenue gets even more extreme if you look at whales as a fraction of downloads rather than spending customers. Most popular games only have a small number of people who pay anything...ever. I'd be willing to bet money that most of Zynga's revenue comes from the top 1% of downloads.
Zynga have more or less admitted this in the past IIRC. No idea if this still exists, but they had at one point setup a ridiculous bank transfer payment program for the largest whales who were bulk buying in game purchases at the tens of thousands of dollars level - minimum $500 transaction to participate.
