A QR code? What did you have in mind for interaction?
As far as I know you'd need at least two devices (the one whose screen is displaying the image with the QR code, and the one you're using to snap a photo of it). And then you'd probably want send the decoded URL back to the original device to load in the original browser.
Edit: Maybe you were thinking about the analog world, but watermarked images tend to show up in the digital space (in mockups especially).
If visiting a URL involves taking my phone out of pocket, finding the QR app, taking a picture, emailing myself the URL, checking email on my desktop, and then clicking the link, I guarantee you that's not going to happen.
Telephone numbers are always use grouping (432-23-43), which makes copying easier. People still have problems with software license codes, although those are grouped too.
However you can just imagine any grouping you like though, by using the power of thinking about stuff. It's a new process they just invented that, get this, lets you think about stuff. It isn't just restricted to thinking about stuff like groups of numbers however, but also works on things like duck identification and fluid dynamics, so it is very flexible.
