Amazon.com, the website of the world's largest online retailer, went down for about 15 minutes for many users across the United States and Canada. It is still not clear what triggered the disruption. Amazon Web Services is designed to ramp up server capacity for customers to prevent outages.

At the moment it has not responded to multiple requests for comment. Users from New York and Toronto to San Francisco got only error messages when trying to access the shopping website. Amazon has $86 billion in annual gross merchandise volume, including its business through third-party sellers, according to consultants at RetailNet Group. Going by that estimate, Amazon processes some $163,622 in transactions per minute on average.

This is the third extremely high profile crash in the last week. Google went off line for five minutes, and Microsoft’s outlook crashed for a couple of days. While crashes are a normal part of computing, these are the busiest and most resilient sites on the Internet. Amazon in particular makes a killing from its cloud based services.