I may have to do some more research, but I have a theory that ICN is:
The first ever deflationary crypto
Bitcrystals is an example that springs to mind. They're burned and the supply is ever-decreasing.
So not the first. There'll be others too, I'm sure.
Interesting. I see they have burnt about 3M BCY in total (6.7% of supply), or $183k worth if you take the USD value at the time of the burns:
Looks like ICN has some catching up to do before it becomes the biggest USD value buy/burned in crypto.