In software development the platform you build on has always been a key piece of how you build applications. For a long time the platform was the system you were developing for, like a PDP-11 or Commodore 64. You were stuck with the processor, memory, and I/O capabilities of the platform. If your application didn’t run well, you had to change your application. Beefing up the hardware was virtually impossible.
Developers have become lazy
Although it is still true we develop on platforms today, these platforms are virtual. Java, .NET, Node.js, and most relational databases are all independent of the hardware they run on. The common practice is therefore to develop an application, and then figure out which hardware to run it on. Memory and CPU capacity are available in abundance, so scaling your application is easy. Well… it was anyway.
Cloud redefines the platform
When developing for Platform-as-a-Service (PaaS), the possible variance of the hardware platform is again limited. You have to deal with the platform as a whole. Aspects such as CPU, memory, network & disk latency, and failure rate, all have to be taken into account when building applications. Most Infrastructure-as-a-Service (IaaS) platforms have similar limitations. IaaS is not just a data center in the cloud which you can shape to fit your needs.
The platform is expanding, rapidly
Cloud vendors such as Amazon, Google, and Microsoft are all adding services we can use in our applications. Data(base) Services, Identity & Access, Mobile Notification, Big Data, Integration, are just a few areas where developers can now use high available and reliable services, instead of hosting their own services on some infrastructure. The Cloud has become the platform, and we need to use the services it offers as-is.