Pro-Freedom, anti-BigGovernment. Everyone should be free to do as they choose, so long as they don't infringe upon the equal freedom of others.
Holders of the Zero Aggression Principle.
The World's Smallest Political Quiz categorizes people along the dimensions of Freedom of economic activity and freedom of personal activity (e.g. sex and drugs), creating quadrants for Conservative (econ free, personal not-free), Liberal (econ not-free, personal free), Populist/Authoritarian (not-free, not-free), and Libertarian (free, free).
Critiques of libertarianism http://world.std.com/~mhuben/libindex.html
Libertarianism makes you stupid: http://sethf.com/essays/major/libstupid.php
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