The common aspect is the individual nature
These technologies share two key aspects.
For starters, they're very personal, with users choosing the ones that fit their work style, user experience preferences, and ways of thinking. IT often ignores the fact that people think differently, and that artisans of all stripes have always had personal favorite tools that simply work better for them -- or seem to, which is the same thing at the end of the day. Just as chefs and construction workers, doctors and sculptors have favorite tools that both reflect them and extend them, so too now can information workers. That's why you get heated arguments over Android versus iOS, or folks who swear by mind mapping and those who just don't get it. They're all right because they're all different.
The other common aspect is that they are all directly applied to the work at hand. They're front-end technlogies, not back-end ones. Individuals use them to accomplish what they've been hired to accomplish, and that individual ownership -- expertise, really -- reflects the person's history and experiences that have made him or her good at the job.
In other words, they are idiosyncratic technologies -- very much the oppoosite of the standardized, almost robotic technologies that IT has been tasked to deliver in the name of efficiency and repeatability, which is why there is often such a clash between IT and empowered users.
With that in mind, all of a sudden IT can see that these tools are not ignorant choices or trivial demands, though they may seem so at times -- but that's beside the point. Instead, they are reflections of the individual and his or her approach to work. That's the point: users choosing tools they believe help them do better at whatever they do.
Understanding this nature of consumerized technology can help IT distinguish the tools as expressions of individuals from the underlying principles and common actions that IT can deliver, aid, and augment through back-end technologies and through flexible governance around data and processes. And it can help both business and IT pros get past the control divide by realizing that like everything else, the technologies in use cover a range from highly specialzied and individual to highly standardized and universal.
Beware smothering individual tools with larger systems
Where IT also has to be careful is in trying to wrap these individual technologies in a blanket of back-end technologies. In many cases, it will smother the tools' individual, local nature -- and cost a lot of money and time in the process. In other cases, it's easy to create parallel information systems -- one for "regular" IT and one for "consumerized" IT -- and end up with a big mess. For example, Forrester Research recently identified 16 technologies to support consumerization. To me, the list is misguided, proposing more areas where IT can spend money and time in an era when budgets are shrinking and demands on IT are already too high.