Activision claim to have sold more than $1 billion of Call of Duty: Ghosts into retail stores worldwide as of day one.
However, the truth lies in the words "into retail". Activision's claim isn't about copies sold to consumers, but rather the units they have sitting on store shelves. Simply, the game didn't break any day one sales records yet Activision felt they needed to issue a press release. The $1 billion figure is a convenient hook for their headline, cunningly deployed no doubt with the expectation of misinterpretation.
Of course, Ghosts has likely sold spectacularly well. Just not quite as well as prior Calls of Duty. And that's the actual story here.