Amazon essentially created the now-massive cloud computing industry back in 2006 when it offered up the web infrastructure services it had developed for its own internal use to outside companies. It's since become more than a $110-billion-a-year industry as more and more companies realize the value of outsourcing their data storage and computing. But not surprisingly, other firms have swooped in to try to capture a piece of the lucrative pie. While Amazon has the early lead and cutting-edge technology, rivals such as Microsoft, Google and IBM each have their own distinct advantages. Who will win the most customers as the cloud continues to evolve? The answer may go a long way towards determining which companies will dominate the tech sector in years to come.