The place I have found QR Codes and URLs to be helpful is with saving trees.
Before an event, I create a single, mobile friendly webpage with all the materials I expect people to ask me for - contact information, PDFs of papers, images, demos, videos, etc.
I create a QR Code for the site. Then, I create a business card with the QR Code, the URL, and a memorable picture (such as my Avatar, my airplane, my dog, etc - something that is relevant to the event and helps the person remember me). If a person asks for information and they can use the QR Code, great. If not, they get the card. Either way, it's a small piece of paper rather than a big bunch of materials.
For people flying into AirVenture, a pocket full of these cards is an easy way to share info about yourself, your build log, your airplane specs, your travels, etc.
You can even leave a big QR Code on your airplane so any picture of the plane, has the QR code in view
PS: for the tech savvy, I suggest you add Google Analytics to the webpage (its free) so you can see some statistics of how many uses, when, where, type of mobile device, etc.