The QR Code has been around since 1994. Fifteen years. Wow. And I've only learned about it, by accident, this year. It is very popular in other parts of the world.
Here is an example, the QR ("Quick Response") Code for this post*:
This could be crocheted or knit into a scarf, or published in some other way.
A cell phone, equipped with a reader for the code, could take a picture of it and then immediately go to the web page.
*The image above is actually a URL which computes the code on-the-fly from the permalink of this post (which is, http://sanbachs.blogspot.com/2009/11/qr-code.html). Below is a static image, captured today (by screen scraping), just in case the image generator goes off-line.