Amazon.com, The Instigator: The "bookseller" captured developers' attention with its early, inexpensive cloud services. Zynga, Netflix, and other stars pretty much live on it.
Google, The Needler: Selling low-cost doppelgängers of Microsoft products such as Office. Developers say Google's platform is more limited than Microsoft's or Amazon's.
Microsoft, The Late Bloomer: Took a while, then went all in. Has cloudified all major products from Xbox to Office to Azure business software services.
Salesforce.com, The Pioneer: Helped drive "software as a service." Now gunning for Amazon and Microsoft with a broader offering.
Rackspace, The Free Radical: Trying to drum up business by creating a cloud based on OpenStack, an open-source software project, and billing itself as free from lock-in.
IBM, The Eminence: Builds custom clouds; sells the hardware and software necessary to build clouds.
HP, The Question Mark: Sells it all—services, servers, storage, software, and data-center space. Still, the new CEO has yet to articulate a cloud strategy.
EMC, The Holding Company: Sells more storage than any company in the world. Private, public—they sell more either way. Owns majority stake in VMware.
AT&T and Verizon, The Phone Guys: Trying to catch up to Amazon with mass-market rentals and more controlled services for big businesses. Emphasize their ability to hitch mobile devices to the cloud.
VMware, The Optimizer: Creates software for making data centers more flexible and efficient. Should win big from the private cloud push.
Dell, The Gear Head: Developing a line of low-power servers to attract cloud computing giants looking to lower their utility bills.
Cisco, The Plumber: Counting on the next wave of Internet expansion to require plenty of switches and routers. Teamed with VMware and EMC to sell "building blocks" to private-cloud makers.