1) Looking at the HN front page, I don't see how that's objectively true. I also don't recall seeing more Nix posts than posts about other topics, particularly popular ones.

2) Has anybody done a statistical analysis of HN posts to see what the top 100 (arbitrary) topics are and how they compare in frequency? Bonus points for a) number of reposts, b) recency data, c) breakdown by month/year, d) fancy graphs