Perhaps the most clear-headed treatment of recent Wikileaks' documents:
Beyond the questions surrounding the massive nature of their disclosure—right or wrong, catastrophic or merely embarrassing—what do these documents reveal about U.S. foreign policy and the nature of diplomacy?Diplomacy in Action by Fred Kaplan
Mainly they illustrate principles about the "great game" of power politics dating back to Thucydides—that nations behave according to their material interests and that a big part of diplomacy lies in appealing to, threatening, or manipulating those interests.
[...]In this sense, Obama's statements [made in his Nobel Prize lecture] marked a resumption of diplomatic practice and principles, as they had been understood by all powers, great and small, for centuries. In this same sense, the WikiLeaks documents—some of them, anyway—show these principles in action.
Had I been the foreign minister of Mongolia, I would have created a special detail within the ministry and devote it solely to analyze these documents--you know, just to understand how really American foreign policy works :)
Addendum: Arguably the best memo within the entire leak :P
A CAUCASUS WEDDING - MOSCOW9533
Ramzan, who danced clumsily with his gold-plated automatic stuck down in the back of his jeans (a houseguest later pointed out that the gold housing eliminated any practical use of the gun, but smirked that Ramzan probably couldn’t fire it anyway). Both Gadzhi and Ramzan showered the dancing children with hundred dollar bills; the dancers probably picked upwards of USD 5000 off the cobblestones. Gadzhi told us later that Ramzan had brought the happy couple “a five kilo lump of gold” as his wedding present. After the dancing and a quick tour of the premises, Ramzan and his army drove off back to Chechnya. We asked why Ramzan did not spend the night in Makhachkala, and were told, “Ramzan never spends the night anywhere.”