You may not have noticed this while you were reading, or while you were checking your favorite websites each morning, but the Web changed dramatically in 2012. According to Mary Meeker, partner at venture capital firm Kleiner Perkins Caufield Byers, in May of 2012, mobile traffic to websites surpassed desktop traffic.

That shift in traffic focus pushed many companies to find solutions for their mobile application strategies. For many, the solution has been to build internal APIs upon which mobile applications can be built. This was the tactic of Netflix, which offers a single API for accessing its giant store of movies and TV shows. End-point clients are simply a natively written window into that API, meaning every supported platform is simply an API-receiving dumb terminal.

2012 was also the year Platform-as-a-Service grew up. Public cloud companies like AppFog, CloudBees and Piston Cloud pushed their hosting platforms as a solution to development woes.

CloudBees, for example, offers online build-and-deploy tools to give developers not only a place to put their applications, but also a workflow to continuously integrate those applications into a server environment. Piston Cloud, on the other hand, is attempting to build a cloud-hosting business based on cutting-edge technologies like Ceph and OpenStack.

But enterprises have long insisted that PaaS won’t work for them. They need an on-premise solution, and that’s why companies like Rackspace, Red Hat and VMware have all moved toward offering products in this space.

VMware’s Cloud Foundry came into its own in 2012. In the spring, the company announced the release of a version of its PaaS designed specifically for local development. Cloud Foundry Micro Edition allowed developers to spin up a local instance of the PaaS, and to test their applications locally, without the need to upload new code to a server.

Red Hat, on the other hand, built its OpenStack-based PaaS, OpenShift, for enterprise users who don’t feel comfortable living entirely in someone else’s cloud. OpenShift was announced earlier this year, and the company released a newer version in November that offered more enterprise features.

2012 was also the year that OpenStack got serious, as indicated by its newly formed governance organization and board of directors. The technical side of the project saw great advances as well, as the platform received some of the first functional components of Project Quantum, which seeks to build software-defined networking tools for OpenStack; and Project Swift, which is an effort to build an ISO repository for storing applications and their environments in a maintainable way.