The #1 mistake made by QR code advertisers is using generic non-mobile web pages as their 'QR-connected' landing page. Web content that's tagged for a QR code or NFC sticker must be mobile and properly formatted for ALL smartphone web browsers (Android, Apple, Blackberry, Windows, ect). Tappinn mobile websites optimize to over 7,000 mobile devices worldwide.
Speed is everything so make sure to design content that can be displayed on a mobile device quickly after the scan. Remember, this is a completely different animal than desktop web design and fresh perspectives must be considered.
Large buttons and easy "touch" navigation are critical to prompting action on the phone. Easy "contact" function can win with convenience alone. Keep the call, email, map and V-card buttons close by! QR codes are by for the best way to prompt users to action in the physical world.