While Platform-as-a-Service (PaaS) has always had its cheerleaders - yours truly included - the harsh reality is that, commercially speaking, PaaS offerings have underperformed relative to expectations for several years running. This is particularly the case among enterprises, which have, by and large, turned a blind eye to the technology.

Past performance notwithstanding, many industry watchers have predicted 2012 to be the breakout year for PaaS in the enterprise. Gartner, for example, reportedly communicated at its November Application Architecture Development & Integration conference its belief that 2012 marks the beginning of a rise in PaaS adoption from almost zero (3% of enterprises) to nearly half of all enterprises (43%) in 2015.

While it remains to be seen whether 2012 goes down in the history books as the year PaaS makes good, much of the groundwork for PaaS' predicted success was laid in 2011. Here are some trends from the past year:

Heroku Beyond Ruby

Salesforce.com's acquisition of Heroku for $250M, an estimated 50-100x revenue, while announced in December 2010, set the stage for a year of brisk investment in PaaS. In January, on the heels of the acquisition, we saw a flurry of Heroku investments and product launches including PHPFog (PHP), Gondor.io (Python/Django), Nodejitsu (Node.js) and CloudBees (Java). With this activity, the reach of PaaS was significantly broadened.

The Rise of Polyglot Platforms

The early flood of single-language PaaS platforms gave way to a move towards multi-language platforms later in the year, perhaps precipitated by DotCloud's entrance in the market with a vision of "One Platform, Any Stack." Established providers like Red Hat OpenShift and Heroku broadly expanded platform support, while the aforementioned PHPFog relaunched as AppFog with a new multi-language platform.

Sam Charrington is the principal of CloudPulse Strategies, an analyst and consulting firm focusing exclusively on cloud computing, big data and related technologies and markets. He can be followed on Twitter at @samcharrington.

The rise of so-called polyglot PaaS platforms, while derided by some as stifling innovation, is significant in that it marks a departure from early "one size fits few" approaches to PaaS, towards something more flexible, familiar, accommodating, and with a bit less lock-in... Just what the enterprise user is looking for.

Enter Cloud Foundry

VMware's Cloud Foundry, which launched in April of 2011 and covered extensively in ReadWriteCloud, was not the first multi-language PaaS. Nor was it the first open-source PaaS, or the first PaaS backed by a major player in enterprise IT. It wasn't the first PaaS to be readily deployable in both public and private cloud environments. Nor was it the first PaaS to embrace the power of an extended ecosystem of developers and partners.

What made Cloud Foundry a game-changer in 2011 is the fact that it was the first PaaS to offer all of those things--on your laptop, in your data center, or in the cloud.

PaaS Ecosystems Flourish

Last but not least, the developer services ecosystems that have formed around the major offerings were expanded greatly in 2011. Users of these platforms can now easily add a wide variety of services such as caching, messaging and databases (SQL and NoSQL) to their applications. These ecosystems are powerful in that they simultaneously have made PaaS platforms more productive for developers and more profitable for providers, while they have reduced the threat of lock-in for users.

The role of these ecosystems is key, and I'm planning to explore this topic further in a future article.

In the meantime, I'll continue rooting for the success of PaaS customers and providers, with full knowledge that they are building upon solid foundations laid throughout the last year.