I only became aware of it when an adult friend started sharing the mischief his elf was getting up to on FB about 8 years ago. And very funny it was too.
I have children now 18 and 20, I swear he didn't exist when they were of the right age. Did I just miss it and they were the only ones who didn't have an elf visiting? They never mentioned it, but if it really has only been around less than a decade, blimey it got traction quickly!