This clip shows magician Marco Tempest employ some clever video animations as part of his act. Sure, it’s not magic per se, but it’s smart – and provides just a hint of the kind of activity big brand marketers are hoping will help them get all viral on the ‘Net. [youtube http://www.youtube.com/watch?v=lcB8CKa73B0&hl=en] See, New York-based creative marketing agency, Site International, this week confirmed it is developing a range of applications for the iPhone and the iPod touch, applications designed to harness the must-have power of the device with amusing viral ads for their client’s products. One is for a yogurt chain interested in mobile coupons,. This ad/past time lets iPhone users create a “virtual smoothie”, mixing yogurt with a selection of fruits and other ingredients on the screen. Once mixed, the viral app lets a user virtually blend the ingredients using the iPhone screen, generating an on-screen bar code they can take to the yoghurt shop to have their choice of smoothie made on the spot. ‘”It’s a fun thing to show off to your friends and we think it can be an effective form of viral marketing.’" said Site Interactive CEO, Alan Ruthazer.