As one of the world's most reliable, scalable, and cost-efficient web infrastructures, AWS has changed the way businesses think about technology infrastructure--there are no up-front expenses or long-term commitments, capital expense is turned into variable operating expense, resources can be added or shed as quickly as needed, and engineering resources are freed up from the undifferentiated heavy lifting of running onsite infrastructure - all without sacrificing operational performance, reliability, or security.

ENGADGET: Amazon Silk browser spins a faster mobile web, courtesy of cloud servers (video)

The standard mileage rate for business is based on an annual study of the fixed and variable costs of operating an automobile.

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On the negative side, revenue growth is decelerating at the same time Amazon is investing more than previously expected in fulfillment centers (fixed assets) and operating and customer service employees (variable costs).

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