A couple of days ago Roland Boon, in a comment here, asked why not believe Amazon's explanation for why they cut off WikiLeaks. I explained that whether I believe or not isn't the question. It's whether I trust them that matters. And will I hold back on what I say about them for fear of being cut off?  

That said, I think it's fairly obvious why Amazon cut them off. It's the 800 pound gorilla in the room.  

Let me explain... 

Today I got a promotional email from Kay Kinton, Senior Public Relations Manager for Amazon Web Services, entitled "Amazon Web Services Year in Review." It contained a paragraph, quoted below, that explains how their government business grew in 2010. 

"Government adoption of AWS grew significantly in 2010. The Recovery Accountability and Transparency Board became the first government-wide agency to migrate to a cloud-based environment when it moved Recovery.gov to AWS in March 2010. Today we have nearly 20 government agencies leveraging AWS, and the U.S. federal government continues to be one of our fastest growing customer segments. The U.S. General Services Administration awarded AWS the ability to provide government agencies with cloud services through the government's cloud storefront, Apps.gov. Additional AWS customers include Treasury.gov, the Federal Register 2.0 at the National Archives, the openEI.org project at DoE's National Renewable Energy Lab, the Supplemental Nutrition Assistance Program at USDA, and the Jet Propulsion Laboratory at NASA. The current AWS compliance framework covers FISMA, PCI DSS Level 1, ISO 27001, SAS70 type II, and HIPAA, and we continue to seek certifications and accreditations that make it easier for government agencies to benefit from AWS. To learn more about how AWS works with the federal government, visit: http://aws.amazon.com/federal/." 

It makes perfect sense that the US government is a big customer of Amazon's web services. It also makes perfect sense that Amazon wouldn't want to do anything to jeopardize that business. There might not have even been a phone call, it might not have been necessary. 

Update: Of course most tech companies do business with the US government, and if they don't they probably want to. For example, a couple of weeks ago, a story came out about the Army equipping every soldier with an iPhone or Android phone. Not saying there's a connection, but a week later Apple banned the WikiLeaks app from their store.