Back while I was working on "Halting State" I had a number of what I called "Halting State moments" — the eerie experience of seeing something I'd invented for a near-future novel's background colour showing up in the news, in real life. It was somewhat disturbing, but after a while I got used to it: at this point, just about everything in that novel (written circa 2005-2006) has shown up, with the possible limited exception of a (the current argument being whether it is in fact a general purpose quantum computing device or something more limited).
Well, I've just had the first real "Rule 34" moment: DNA testing is now being used to enforce dog-poop by-laws. (It's only a matter of time before the police drones come with dog-poop samplers ...)
Have you spotted any harbingers of the world of "Rule 34" yet? And if so, what and where?