This week's book giveaway is in the General Computing forum. We're giving away four copies of Arduino in Action and have Martin Evans, Joshua Noble, and Jordan Hochenbaum on-line! See this thread for details.
QR code can be said an extension for barcode. While the barcode use much more space for less number of character and does not support UTF chars like kanji or kana, the QR code support kanji,kana and takes much less space.