It's early days with the developer preview of OS X 10.8 Mountain Lion, but there are already a few interesting tidbits peeking out around the corners of the developer NDA. We've heard that the system includes a new 'CoreRecognition' framework and a 'CRCodeRedeemer' class, both of which appear to be built for turning barcodes into app licenses.
While marketers can use a 2D barcode now to lead customers to their website or app, that doesn't necessarily translate to an app download or purchase. If this framework operates as it appears, that won't be a problem in Mountain Lion. Specially-crafted barcodes would let you simply hold up a card to your Mac's camera to download a prepaid app from the Mac App Store (or from iTunes, possibly). That's a new level of convenience for developers who want to give away copies of their apps at face-to-face events.
This technology would be even more interesting if Apple's 2011 patent application for 'digital handshakes' ever sees daylight. With barcodes or data embeds printed on your devices with invisible ink, you could log into your Mac just by waving your iPhone at it -- which would require that your Mac have some barcode-reading savvy.