QR codes or Quick Response Codes have been very popular in Japan. It is recently on that these have started catching eyes of our generation. The reason why they are going to be more popular than a standard barcode is that they can store (and digitally present) much more data, including url links, geo coordinates, and text. Instead of having a barcode reader with you to scan and read barcodes, your cell phone can read and decipher what all is stored in the QR Code.
Cell Phone Readers are available as free apps in the market and it takes only a minute to download this and install on your phone. Though their usages are still in infancy but we may see the trend catching on quite a big way. Google Docs have a gadget which can help you generate the QR code from spreadsheet. The generated code can be placed on your business card so that it would be easy for others to scan and store your contact details in their cell phones.
How to generate your QR code
Open a Google doc spreadsheet and use a cell/column to store the data, urls etc. Now go the Insert option on the top menu. Insert->Gadget->Add a Gadget->all->QR code gadget. Select this option to generate your QR code instantaneously.
What all you can do with QR code
One can use QR codes as
Twitter, Facebook, MySpace IDs
A link to your YouTube video
There are many ways in which you can use them on to your site, business cards leaflets, brochures, presentations etc.