QR codes. Big in Japan, and China, right?
But lame in the US.
Or, maybe, QR codes have been a tech tortoise: advancing slowly, improving slightly, getting a tiny bit more popular every year?
That would match my experience. I found QR (for "Quick Response") technology to be the most solid, dependable connectivity tech out there.
To add to their appeal: there are plenty of free QR apps on both Android and iPhone devices. The iPhone's native camera app will automatically recognize a QR code, and display the link in Safari.
So QR, also, got a slot on the control panel.