Millennial Media: iPad mini impressions grew 28% per day by Philip Elmer-DeWitt @FortuneMagazine December 10, 2012, 5:58 PM EST E-mail Tweet Facebook Google Plus Linkedin Share icons Source: Millennial Media FORTUNE — “The iPad mini is a game changer,” writes Millennial Media‘s Matt Gillis in a blog post Monday. “Every holiday season there seems to be one particular item that stands out as the ‘must have gift’ of the year,” he writes, “and in 2012, early figures lead us to believe that this could be the iPad Mini. Truth be told, don’t tell my kids but there are already two sitting under our tree at home.” His evidence: Impressions from Apple’s AAPL new tablet recorded by Millennial Media’s mobile advertising partners grew an average of 28% every day in November. By comparison, Amazon’s AMZN Kindle Fire, 2011’s hot tablet, grew 19% per day during the comparable period last year. Meanwhile, Apple’s iPad mini supplies are rapidly catching up to demand. Ship times on the company’s online store are now down to one week.