He's always written about conformism and wealth. See "Why Nerds Are Unpopular" (2003) [1], "What You Can't Say" (2004) [2], and a lengthy discussion of what wealth is and what it means for society in "How to Make Wealth" (2004) [3]. All of these are featured in his book, "Hackers and Painters".

[1] http://paulgraham.com/nerds.html [2] http://paulgraham.com/say.html [3] http://paulgraham.com/wealth.html