In Newtown, Adam Lanza carried hundreds of rounds -- enough to kill every student in the Sandy Hook Elementary school if he had not been stopped. But he also attempted to destroy his hard drives to cover his pre-rampage digital tracks. Clearly he feared the data he left behind.

The list of examples can go on. Seung-Hui Cho, the Virginia Tech student who committed the worst mass shooting in American history, bought two semi-automatic handguns, along with hollow point bullets, from dealers in just over a month. A few weeks later, he purchased 10-round magazines from a seller in Idaho through eBay. All this was after he failed to disclose information about his mental health on the gun-purchasing background questionnaire (specifically, that he had been court-ordered to outpatient treatment at a mental health facility).

Though we call this kind of thing big data, a database tracking ammunition and gun purchases would be, in fact, tiny. As someone who deals daily with the deluge of data currently inundating the marketing world, I can say based on experience that this kind of record-keeping would be an inconsequential task to set up, and the data science to analyze it trivial. Massive efforts are going into far smaller things, such as which TV program is most engaging for soap buyers who have DVRs, and which pitcher/batter combinations lead to better baseball.

Let me give you some numbers. According to the ATF, about 4.5 million new firearms, including approximately 2 million handguns, are sold in the United States every year, along with roughly 2 million more secondhand ones. No one knows how much ammunition is sold yearly in the country, but as a yardstick, the U.S. Military bought 1.8 billion rounds in 2005.

That sounds like a lot -- but it isn't. Not in today's data-driven private sector. This data would fit on a thumb drive you can buy at any Best Buy and still leave room for the transcripts of every Rush Limbaugh show ever.

By numerical contrast, Netflix, with 24 million users, will stream several billion movies this year, and Walmart sees many times this in transactions daily. Twitter had 150 million tweets about the 2012 London Olympics, and 12 million in the first hour after Osama bin Laden was killed.

Big, complicated data, this is not. But the political will to create a firearm and ammunition purchasing database will need to be massive if we're ever going to have one. Michael Bloomberg, in his anger over the Sandy Hook rampage and armed with his reputation and personal bankroll, may be the only person able (and willing) to counter the NRA, whose opposition to any minor gun "restriction" has kept us in political paralysis for decades as tens of thousands of Americans die every year from gun violence. The NRA's opposing argument will be that it is an invasion of privacy for gun owners. But in our post-9/11 world, we already have ample precedents to do this. Go into any airport and see what happens when you try and buy a ticket with cash on the next flight out. You will not board the flight without security calling you aside for questions. Go into a pharmacy in dozens of states and buy cold medicine and you will be asked for ID and tracked in the NPLEX database. Go on the Internet and you can read that the cellphone carriers told Congress that U.S. law enforcement made a staggering 1.3 millions requests for customer text messages, caller locations, and other information just in 2011. And that the number of requests had doubled in the last five years. Most of this cell phone data is requested without even a warrant issued by a judge.