In the first wave of computing there was virtually no user interface, comprising little more than instructions
written on punch cards which were loaded into a hopper then read by the computer with the results given to the user via a printout. The second wave introduced what we now know to be a user interface, a display with characters and graphics along with a keyboard and mouse. The display evolved from simple monochromatic characters to full color graphics with ever increasing resolution over time and the keyboard and mouse technologies evolved to be smaller and integrated with trackpoints and trackpads. However, the basic elements of a small TV like display, with a keyboard and mouse beneath it, have remained constant for a remarkably long time. What appeared on that display and how a user interacts with it has remained surprisingly constant as well, especially from the time that the concept of programs running in separate windows was introduced.
While there were minor predecessors, the major shift into an entirely new form factor came with the introduction of the iPhone. We're now so used to smartphone UIs that many people forget that we hadn't ever experienced one until Apple introduced its game-changing device. The smartphone form factor existed before the iPhone, but Apple totally redefined it. Once users were used to the iPhone user interface, the adoption of the larger form factor iPad was incredibly easy because it was virtually identical. Like the smartphone, the tablet form factor also existed prior to the iPad but again Apple redefined it dramatically. Key to that redefinition was the perfected use of multi-touch. Interacting via multi-touch is so pervasive now that it isn't uncommon to see people walking up to screens in places like hotels, airports, and stores expecting to be able to interact with them with touch only to be really surprised and disappointed when they turn out not to support touch. That's when you know that we've experienced a paradigm shift as a society. Touch has been in university labs for decades but it took Apple's dedication to design excellence of the entire user experience to perfect the technology to create this paradigm shift. 
Another paradigm shift in interaction modality has just started. This one involves the use of speech. Again, speech technology has been around for decades and has been used commercially successfully as well but mostly in niche markets like voice response systems and dictation systems. Apple's Siri is still in beta, a product designation Apple very rarely uses, but promises to do for speech technology what the iPhone did for touch technology - make it a pervasive and paradigmatic change in society.
There are two major insights to glean from these fairly recent advances. The first concerns how these changes took place. In each case, the basic research and foundational technologies as well as even some commercial applications existed for decades prior to the paradigm shift. It was Apple's approach to design that made the difference. The design of everything, from the industrial design of the physical elements of the device (glass, case, bezel, etc.), the visual and interaction design of the operating system and key apps, the engineering design of the internals (processors, memory, battery, GPS, etc.), the manufacturing design of the production line, the design of the website and app store, the design of the content review process, the design of the payment and app download system, the design of the stores, the design of product support, all the way to the design of the product secrecy and product announce/launch systems. Many people like to jump to simple conclusions that these paradigm changes were brought about by this or that individual element but I believe that it was Apple's focus on the total customer experience and all the elements that impact it that was critical. Designers planning a product that they hope will transform an industry need to focus on all of these aspects of design.
The second major insight to glean from these paradigm shifts is the need to rethink how all future products in any market should fit into these major paradigmatic changes in form factor, device, and interaction modality. Designers now need to understand deeply how users are using these technologies in order to design products optimally leveraging them. This is a challenge for many because, as pointed out above, form factor, device, and interaction modality hadn't changed virtually at all for decades. However, these recent changes are so profound that it really does require designers in any market to sit up and take note and consider how users in their markets may be changing.
Having explored paradigm changes we've already witnessed, let's give some thought to where these may go in the future and what other paradigms we may witness in the future. While the computer, smartphone, and tablet form factors and the touch and speech interaction modalities have mostly developed independently, the emerging trend is for them to become more consistent and a future paradigmatic change may involve them integrating deeply. We're seeing the beginnings of changes being made largely to computer operating systems like Apple's OSX to make them more similar to device operating systems like iOS. Apple is making the change gradually with each update to the OS, which is a wise approach that minimizes the magnitude of the change but still moves drives consistency. We're also seeing the very beginnings of a move to integrate form factors, devices, and interaction modalities. Responsive design is part of this trend, as is the enablement of touch and speech pervasively across devices. We're also seeing some degree of cloud based seamless access integrating content and data across devices. We're also seeing that integration spread to even larger form factors like TVs and digitally enabled physical window panes. Some call this a post-PC era, my sense is that we're witnessing a plethora of form factors which in PCs, ensuring that each of these can suit the wide characteristics and contexts of use into the future.
We're living in exciting times that require designers to be fully aware of, intimately knowledgeable about, and be able to leverage the benefits of these incredible paradigm shifts in technology and people's use of them.
