Though Amazon.com (Nasdaq: AMZN) might have the more popular cloud computing offering compared with Microsoft (Nasdaq: MSFT), the two companies together dominate the cloud market. That's helping to make Seattle the global cloud capital. That is one upshot of a January survey of 1,060 technology professionals across businesses of all sizes conducted by RightScale, a cloud infrastructure management company. Amazon Web Services, or AWS, was the most commonly used cloud computing service among survey…