iPhone and iPad sales: Two Christmas Day data points by Philip Elmer-DeWitt @FortuneMagazine December 28, 2012, 3:59 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Click to enlarge. FORTUNE — Given the blow-out iPhone and iPads sales Apple AAPL reported in its 2011 holiday quarter — up 128% and 111% year over year, respectively — the Wall Street analysts we’ve polled expect that breakneck growth to slow considerably in the quarter that ends Saturday. They think Apple’s Q1 2013 is going to be what they call a “tough compare,” and they’re looking, on average, for year-over-year unit sales growth of 28% for the iPhone and 48% for the iPad. But some of the data coming in from holiday sales suggest that those estimates may be too conservative. In particular: Flurry Analytics reports that 17 million Apple iOS and Google GOOG Android devices were activated on Christmas Day, up 250% from 2011. Flurry, unfortunately, doesn’t tell us how many of those were Androids and how many were Apples. Distimo‘s data was more platform specific. It reported a “very appy” Christmas Day that saw downloads on Apple’s App Store increase 87% year over year. While less than the 3X increase Distimo reported in 2011, it suggests a bigger bump in unit sales that the Street is expecting. One more stat, this one from Chitka, which measured ad impressions from various manufacturers’ tablets in the pre-Christmas week of Dec. 8-14. Their data are shown, as usual, on a scale of 100 iPad impressions. “Eighty-seven percent of the tablet web traffic in North America is generated by iPad,” is how Chitika’s Gabe Donnini interprets the chart below. VentureBeat‘s John Koetsier puts it in starker terms: “For every 100 web pageviews on an iPad, a Kindle gets 5, a Galaxy gets 3, and a Surface gets 0.22″ Click to enlarge.