It basically breaks morality down in to five precepts:
• Harm/care. It is wrong to hurt people; it is good to relieve suffering.
• Fairness/reciprocity. Justice and fairness are good; people have certain rights that need to be upheld in social interactions.
• In-group loyalty. People should be true to their group and be wary of threats from the outside. Allegiance, loyalty and patriotism are virtues; betrayal is bad.
• Authority/respect. People should respect social hierarchy; social order is necessary for human life.
• Purity/sanctity. The body and certain aspects of life are sacred. Cleanliness and health, as well as their derivatives of chastity and piety, are all good. Pollution, contamination and the associated character traits of lust and greed are all bad.
The general answer is that liberals and conservatives value different aspects of this. I'm not sure I agree with this - I'm not convinced that you can neatly divide and separate them when you are looking at specific issues. For example, the article says that Liberals generally are most concerned with the 'harm' impulse, but that Conservatives aren't. However, it later brings up abortion, and says that it is a touchy issue for conservatives because of their concern with the 'purity' impulse - essentially because of their believe in souls and the sanctity...of.... life? How is this different from harm? I would think that attitudes to abortion show that harm certainly *does* register as an important concern for conservatives, in certain contexts at least. Its not so neat as first appears.
Despite some misgivings, however, it is an interesting notion, and potentially useful if used carefully... Obviously I thought it was worth sharing :V