Apple is expected to unveil the iPad Mini this week and expects to sell millions of units in the run-up to the holiday season. With studies suggesting that smaller-screened tablets get a better marketing response, the new device is potentially a big deal for brands. "We know from industry studies that 56% of tablet owners make over $75,000, and 46% have made a purchase after interacting with a tablet ad, so this creates a new, potentially very lucrative frontier for digital marketers," said Kurt Hawks of mobile ad network Greystripe.