In the first Indie Bundle [http://www.wolfire.com/humble], they didn't show these results until the last days, and the stats were similar. Linux Users weren't trying to show off, it was something that just happened.
Means are still spectacularly unstable to small numbers of outliers. They're more stable with higher numbers of samples, but so is any given measure of centrality.
So, a few Linux users donating $500 could sway an identical distribution to the Mac or Windows users.
