One foundation of all the IoT hype (or excitement depending upon your viewpoint) is the huge number of IP addresses that are being connected every day and extrapolating out to 2015 it adds up to billions. So where does all this data about data come from? The Gartner's and IDC's have their guesses but perhaps a more reliable source is Cisco and their VNI index. At least Cisco knows (or should) how many IP addresses are being added to those lookup tables. The great news is that you can download the data that forms the index and customize it for your own needs which is cool.
The data is here: http://www.cisco.com/en/US/netsol/ns827/networking_solutions_sub_solution.html
If you are a skeptic I suggest you take a look at the admin screens on your home wireless router and count the number of IP addresses that connect to it on a regular basis, you may be surprised, I was.
My NetGear home router sees 17 IP addresses on a regular basis, that's laptops, iPhones, an iPad, a Tivo, 2 printers, a Twine and an outdoor weather station. How many do you have?