NOT: QR codes
These Rorschach tests for nerds were once envisioned to be the easiest and cheapest way to hyperlink the physical world. Just point your smartphone camera at one, click, and you're transported to a website for more information. The problem? Only 9 percent of consumers used a QR code last year, according to eMarketer, a number that's not expected to grow very quickly in the future. Worse, given how thoroughly they mask dubious URLs, they've become a new way to distribute malware and phishing attacks -- proving once again that what you don't know can hurt you.