The following is a QR Code with the information aruninte.blogspot.com encoded.
Facebook started experimenting with it. in SXSW 2010 it was used in ID cards. The advantage is that it is easy to store information in mobiles. The disadvantage is a reader is required.
Make sure your phone can scan a QR code with its camera
When you see a QR code, use your phone's application to scan it
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