Regardless, in a ballooning market, everyone has a shot. Google Compute Engine, currently in beta, claims it will have a performance and reliability advantage. HP Cloud seems willing to bend over backward to accommodate particular enterprise needs -- and promises "convergence" with its private cloud offerings to support unified management.
Windows Azure may be the most interesting case of all. Over two years ago it officially launched as a PaaS catering to Microsoft developers who wanted to build and deploy applications in the cloud. Adoption was not brisk. In the summer of 2012, Microsoft quietly added IaaS -- including support for Linux and MySQL -- backing off its long-held assertion that PaaS was the vastly superior option.
Coding in the cloud: For lightweight apps only
Of course, Azure has plenty of PaaS company; Google's App Engine, VMware's Cloud Foundry, Red Hat's OpenShift, and Salesforce's Force.com and Heroku are the most prominent. But there are many smaller players, including Zend Developer Cloud for PHP coders, CloudBees for Java programmers, Joyent (also an IaaS provider) for Node.js programmers, and AppFog, which supports multiple languages.
As far as I can determine, PaaS has not gained much traction with enterprise developers at all. Instead, small ISVs that build and deploy mobile or Web apps -- or agencies contracted by enterprises to build public-facing Web apps -- tend to form the bulk of PaaS customers. It's not hard to see why: These platforms provide a quick way for independent developers to dev, test, and deploy Web apps, yet enterprises are none too thrilled about putting their intellectual property in the hands of PaaS providers.
PaaS offerings by their nature provide one environment for many developers, whereas developers of more complex apps tend to have a multiplicity of tools and ways of doing things, including multiple languages, which may or may not be the same mix offered by a PaaS. Again, the road leads to IaaS providers, which enable customers to set up environments any way they like and offer bundles of ready-to-use database and app dev services besides.
That said, I think we'll see a significant increase in enterprise PaaS adoption in 2013 -- just not by core enterprise developers. Instead, at the departmental level, those frustrated with the slow pace of enterprise app dev will turn to PaaS to create the apps they need on their own. This is probably already happening more than enterprise IT knows.
Meanwhile, IDC has identified a potentially vast segment it dubs "industry PaaS." The idea is that businesses themselves will create industry-specific PaaS offerings that will enable other businesses in the same vertical to build and deploy vertical apps -- and even sell those apps to each other in app stores. The New York Stock Exchange already has a PaaS offering for trading apps; Johnson Controls has one for energy-conserving "smart building" apps. If it takes off, industry PaaS will provide a clear indication that the cloud is loosening enterprise IT's grip on core technology.