While Mac Nerds had very little to jump-up-and-down about during Apple's 'Let's Rock' event in SF—aside from the launch of the new super slick iPod Nano, and perhaps the reassuring appearance of the equally slender, though vibrant Steve Jobs—the launch of the latest iteration of iTunes could quietly be the real show stopper.

Perhaps the most significant new feature or upgrade, apart from the new grid layout and iPhone-ish presentation, is the addition of the 'Genius' capability. Genius is essentially an automated DJ that once activated can build genre-based play lists based on the music in your library. 

Big deal, I hear you sigh, nothing new to write home about there, Amazon and the ill-fated Pandora offer(ed) similar attributes, OK, but then take a quick shufty over to the 'Genius Sidebar' and you can see just what Apple is cunningly doing. With the click of the mouse iTunes will seamlessly link highlighted songs with it's own 'Genius' list of over 25 songs and artists that it thinks may tempt its users to purchase .

The iTunes music store, as with the UK-based Last.fm, also allows music lovers to share their play lists online, thus simultaneously building a valuable social networking forum. Last.fm which was sold last year to CBS Interactive for $280 million which would surly be eclipsed should Apple ever decide to sell.

By my reckoning alone, just with a little bit of code tinkering Apple has provided access to an almost infinite source of revenues. iTunes was worth $570 million in revenues last year, so with its 500 million users—and counting—I think it is safe to assume that this DJ recommendation to-purchase feature will add beaucoup bucks to the company's bottom line.

Think of 'Genius' as the digital equivalent of putting the candy bars by the checkout in your local supermarket.

Just don't expect to find anything by AC-DC or the Beatles, yet.