At the heart of the argument between the EU and Facebook is a question which could determine the very survival of the social media giant.

For though Facebook is one of the world's biggest companies, worth almost half a trillion dollars, that value is based almost exclusively on what it does with users' data.

Or, as Mark Zuckerberg responded at a Senate hearing in April when asked how Facebook remained free: "Senator, we run ads."

If Facebook can continue to use user data to target those ads with precision, then it will continue to make - and be worth - a fortune. If, however, either regulators or users get fed up with their details being used to sell stuff, the tech giant really isn't worth all that much.

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Amazon's data harvesting, for example, is also being scrutinised by the EU. But Amazon's dominance is driven not just by data but also by an enormous physical delivery infrastructure (and in web hosting).

Facebook, by contrast, depends far more on that intangible decision its customers make to share their information. If they stop wanting to do so, Facebook's business proposition is holed - below the water line.

Hence the sensitivity over the current battle. Internet sites tend to worry that spelling out, in the clearest and boldest terms, what they do with data might scare users away - just as cigarette manufacturers worried about putting health warnings on packets.

And while warnings did not always influence hardcore smokers, evidence suggests that over time, they changed perceptions of smoking.

Facebook, already facing fallout from the Cambridge Analytica scandal, understandably dreads an equivalent poisoning of its own brand. So its inclination is to resist EU demands. The result is part of a new global battle to set the regulatory framework for the 21st-century tech-driven economy.

That battle is primarily being waged in America and China - polar opposites where the "wild west coast" model of Silicon Valley vies against the rigid state control demanded by Beijing.

In between, the EU is aiming to carve out a third way, a Goldilocks alternative which enshrines consumer rights without crushing innovation. With Europe so far behind the US and China in terms of scale, some in tech describe this middle way as potentially the Continent's biggest advantage.

The spat between Vera Jourova and Mark Zuckerberg, then, is about a lot more than one company's terms of service.