Flurry has bits of tracing code in over 140 thousand apps, and they boast that they detect approximately 100% of all new iOS and Android devices activated each day. I'd hope they're right; if they missed some then the total number of activations would be even higher.
And that figure doesn't include ereaders, which would likely add a couple million (at least) on top.
Let's put that number into perspective. More gadgets were activated on Christmas than there are people living in the DC metro area. The 6.8 million devices would be enough for everyone in Cairo, Egypt to get a device. It's also about the same as the population of Laos. Yes, there were enough gadgets activated on Christmas to populate a small Asian country. Now that is an impressive number.
But wait, there's more. Flurry also reported that they saw 242 million new apps being downloaded on Christmas day. That's more than double the daily average for the month of December, as well as over double the activity on any other day in their record - except 24 December, which saw an impressive 150m downloads.
Flurry is also expecting the elevated download levels to continue from Christmas through New Year’s Day. They expect to see approximately 1 billion total downloads over the next week.