When talking about IoT, people will referred to the billions of devices that are projected to be connected by the next decade. That can be hard to wrap your head around, so keep two things in mind -- your current data plan and the ubiquity of cell phones, in terms of sheer number; Wikipedia tells us it was around seven billion in 2014.
Today, Mashable is reporting that in five years, it is estimated the average mobile user in the US will use 22GB of data per month -- better lock in that data plan now! Assuming IoT services scale similarly, it's interesting is to anticipate how that would impact bandwidth for connected devices. As the mobile infrastructure scales, I would assume IoT would as well; especially if it is built on top of cellular technology.
And while IoT is a growing market projected to include several billion more devices in the coming years, that's nothing new. But In the linked Ericsson report, not only does it agree with that projections, anywhere from 16 to 28 billion devices by the early 20s, but also by 2018, we may see IoT devices overtaking mobile devices as the largest category of connected things.
While IoT traffic probably won't overtake mobile traffic for a while (the majority of mobile traffic is video), with the projected increase in both number of devices and bandwidth, it will be interesting to see what sort of services become available and how current services scale.