Microsoft Azure: Fastest-Growing Big Cloud Provider

When it comes to cloud services market share, Amazon is still the market leader but Microsoft now enjoys the fastest revenue growth among the big 5 cloud providers, according to Synergy Research Group.

Amazon Web Services now commands 28 percent of the cloud infrastructure market, followed by Microsoft (10 percent), IBM (7 percent), Google (5 percent) and Salesforce.com (4 percent). 

In terms of growth rates, Microsoft (up 96 percent) showed the greatest progress in 2014, followed by Google (81 percent), Amazon (51 percent), IBM (48 percent) and Salesforce.com (37 percent), Synergy estimates.

During an earnings call last week, Amazon vowed to start disclosing its AWS revenues at the end of each quarter. That statement triggered applause on Wall Street. Analysts viewed the statement as a sign that Amazon believes it is pulling away from cloud rivals.

Still, competition remains fierce. Microsoft CEO Satya Nadella has diversified the Azure cloud strategy far beyond Windows Server -- embracing Docker and other open source technologies to strengthen the company's cross-platform strategy. 

Similarly, Google and VMware are partnering up, bringing more and more of Google Cloud Platform services to VMware's hybrid cloud strategy.

For its part, IBM has been adding SoftLayer cloud data centers worldwide to further expand that business. IBM claims to generate $7 billion in cloud-related revenues annually, but much of that involves consulting, hardware and software sales to hybrid cloud customers -- rather than "as a service" revenues. In the as-a-service space, IBM now has a $3.5 billion annual run rate -- based on December 2014 revenues.

The dark horse in the cloud race is Rackspace -- sitting at 3 percent market share but well-known for its Fanatical Support expertise.