A Quick Response Code (QR) is a type of barcode that can be read by smart phones and other dedicated devices. The code captures information, such as a website URL, and directs the device scanning the code to, in this case, the URL’s location on the internet.
QR’s are used in a variety of ways. Relative to online business, they are used in offline print, e.g. billboards, brochures, etc., usually in conjunction with the landing page associated to the product or service being advertised. For instance, if my company was to release a new print brochure and one of our goals was to increase traffic to our home page, we may use a QR at the bottom of the brochure alongside the typed URL. Codes can be generated on many free websites. Here is a great one.
Below is a working example for the URL www.myriadcore.com:

If you download your smartphone’s QR app, available free at your device’s marketplace, and scan over this image, you will be directed to the corresponding URL.
The many creative ways to use QR’s I’ll leave to you. However, there is a caveat I’d like to point out. As URL’s get longer, the code becomes more complicated, making it harder for smart phones to read. To keep the codes at a reasonable size (you don’t want to make them too small), and at a reasonably simple composition, you can use a URL shortener.
For instance, here is a long URL directing to an image:
Using the simple and free URL shortener here, the long URL above becomes this: http://bit.ly/mN3Kas,  which can be in turn pasted into the QR generator to produce a code that is simple, reasonably sized, and directs to the intended landing page.
#Myriad Core is a website optimization company