QR Code

2D BarCode http://en.wikipedia.org/wiki/QR_Code

Increasingly used for sharing URLs by printing (or on-screen). (You take a picture with the camera.)

• Aug'2024: Boris Mann is putting his vCard in it.
• JuJ'2023: I used HiHello commercial service that provided a "business card" page for you from your data, with an associated QR-code

make your own: https://goqr.me/

Competes with less-open Data Matrix code.