Good news for the U.S. is really bad news for Syria. And Libya. And ... Greenland.

What happened in Syria this week -- a wholesale disconnection from the Internet -- could happen anywhere. But it's more likely to happen in some countries than others.

The web services firm Renesys often analyzes that risk -- for, say, companies that are deciding which countries might make good hosts for data centers. And, in light of the Syria situation, it has conducted "a census, from our own view of the global Internet routing table, of all the domestic providers in each country who have direct connections (visible in routing) to foreign providers." Using that information, the firm created the chart above.

The illustration here is mostly unsurprising: Syria, Libya, Tunisia, Myanmar -- countries led by volatile and/or autocratic regimes -- are the most at-risk, while (relatively) stable democracies and commonwealths like the U.S., Canada, and European nations are relatively resistant to blackout. 

The most common risk factor, unsurprisingly, is centralization. A robust Internet architecture is a distributed Internet architecture -- one with built-in redundancies and, crucially, one that is modular enough to prevent the kill switch capabilities that can empower bad actors to act badly. "The key to the Internet's survival is the Internet's decentralization," the Renesys report notes, "and it's not uniform across the world."

Regulation is another risk factor. Per Renesys: 

In some countries, international access to data and telecommunications services is heavily regulated. There may be only one or two companies who hold official licenses to carry voice and Internet traffic to and from the outside world, and they are required by law to mediate access for everyone else.

Under those circumstances, it's almost trivial for a government to issue an order that would take down the Internet. Make a few phone calls, or turn off power in a couple of central facilities, and you've (legally) disconnected the domestic Internet from the global Internet. Of course, this level of centralization also makes it much harder for the government to defend the nation's Internet infrastructure against a determined opponent, who knows they can do a lot of damage by hitting just a few targets.

So the chart is based on diversity. And based on criteria and observations like these:

• If you have only 1 or 2 companies at your international frontier, we classify your country as being at severe risk of Internet disconnection.
• If you have fewer than 10 service providers at your international frontier, your country is probably exposed to some significant risk of Internet disconnection.
• If you have more than 10 internationally-connected service providers, but fewer than about 40, your risk of disconnection is fairly low.
• Finally, if you have more than 40 providers at your frontier, your country is likely to be extremely resistant to Internet disconnection.

These are fairly common-sense. But it's good to put numbers behind risk, and nice to be reminded of how varied the world's Internet infrastructure is. And, specifically, how fragile connection is for so many countries. This is something, Renesys points out, that will likely be a subject of discussion at next week's World Conference on International Telecommunications. Though discussion, of course, won't itself lead to improvement. "Without some strong legal prodding and guidance from the telecoms regulator," Renesys notes, "significant diversification in smaller markets with a strong incumbent can take a long, long time."