Early sales numbers for highly anticipated games, especially for games like Call of Duty: Black Ops 2, are becoming harder and harder to evaluate. At first, the numbers were purely unit-based, with publishers like Activision boasting about the sheer amount of retail copies that were flying off store shelves within the first day, week, or month of release.

Now, however, publisher’s strategies have changed, and they have begun to seek out new ways to emphasize their product’s importance, or dominance, in the video game market. And that is why today we bring you the announcement that Black Ops 2 has grossed $1 billion in a record-breaking 15 days.

This tally eclipses Modern Warfare 3‘s milestone of $1 billion in 16 days, and as Activision was kind enough to point out, passes the Avatar‘s record of $1 billion (in worldwide sales) in 17 days, but let’s be fair comparing a $60 game with a ~$10 movie ticket is not a fair comparison. Grand total, the two are in a similar category, but Cameron’s flick had to get A LOT more people interested, and had the legs to stay relevant for several months.

Nonetheless, it doesn’t come as all that much of a surprise that Black Ops 2 surpassed Modern Warfare 3 in the race to $1 billion, though, as Activision had already revealed Treyarch‘s latest grossed $500 million in 24 hours. By comparison, Modern Warfare 3 grossed $400 million over that same time span a year ago.

As you can see, it’s all about skewing the numbers in a publisher’s favor these days, with Activision now choosing to mention sales dollars rather than units. This decision also lends credence to Michael Pachter’s prediction that Black Ops 2 unit sales were slightly below that of Modern Warfare 3 for the month of November.

The lack of a 5-day total is equally intriguing — another omission that suggests Black Ops 2, in some categories, is trailing behind Modern Warfare 3. Up until the launch of Black Ops, many considered Treyarch’s COD offering to be the lesser of the two brands-within-the-brand but all that changed when Blops eclipsed Modern Warfare 2‘s 2009 records. Still, generating $1 billion in sales is nothing to scoff at, and should make Black Ops 2 the ‘Biggest Entertainment Launch’ of 2012 — a title that Activision has loved to toss around in past years.

But what does a lack of boasting at key milestones suggest? Is the Call of Duty franchise waning in the face of gamer fatigue and growing competition? Share your thoughts in the comments below.

Call of Duty: Black Ops 2 is available now for the PS3, Xbox 360, and PC.