If you have a place of business where customers have to wait in line, sit in a lobby, or sit at a table, then you have a perfect opportunity to invite those customers to engage with you and tell you how you are doing. The Facebook and Twitter possibilities are nearly endless for such businesses, as well.
You can also invite customers to join your e-mail list while they wait by sending them to a simple squeeze page with an incentive. See Chapter 7 for details on squeeze and lead capture pages.
You can also have your customers engage with you in creative ways with texted pics, Twitter or Facebook posts in “real time” (they don't have to wait until they get home), or with other services like Groupon.com, Yelp.com, Loopt.com, Gowalla.com, or FourSquare.com.
QR codes (also called “2D codes”) are starting to show up everywhere.
They are basically barcodes with a bit more information contained inside. Google is spending a lot of time and money trying to make these codes go mainstream. As more and more people have smartphones, the potential uses of QR codes is skyrocketing.
A QR code looks like this:
Wikipedia article on what QR codes are: http://en.wikipedia.org/wiki/QR_Code ...