With the expansion of ways for people to communicate, spread information, and connect on the internet and social media has come a rise in the ability of people to cross digital boundaries, for good and for harm.

Nations, organizations, and all kinds of entities have digital as well as physical borders —  systems intended to provide access to one another in a group and to regulate its access to others. The open architecture of the internet has rendered digital borders relatively open and permeable even as we debate the level of permeability of physical borders. To be sure, it is a challenge to maintain boundaries, to keep outsiders from intruding, and prevent the often quite serious problems that can arise in an open system. When terrorism strikes, we often hear calls to close borders altogether.

In a time of heightened fear and polarizing rhetoric, it is important to keep in mind that the internet and social media are key elements both of terrorist radicalization and of efforts to gather intelligence against those same groups. In some cases, the same message boards that enemy groups use to amass resources are used to gather evidence against them. Digital spaces can be used for good or for ill, sometimes simultaneously.

Certainly, when digital spaces are used to harm, or are hacked into with information is re-routed or re-purposed (or destroyed or made unintelligible, as by a computer virus), the results can be devastating. Individual lives as well as critical information systems can be destroyed. Monetary systems, power grids, websites, personal information, and basically anything that is gathered, organized, and stored via computer can be affected when digital security is compromised. These computer crimes should and must be prosecuted.

Large-scale cyberattacks can take two forms: information attacks and infrastructure attacks. In the former, personal information can be retrieved, made public, and used to harm or embarrass or generate fear. In the latter, critical services can be disabled. Messages can be sent out under the ISP name of another organization, websites can be defaced, money and information can be stolen, sabotage can take place, threats can be made. Large data breaches, such as that in which the personal information of 83 million J.P. Morgan Chase customers was stolen in 2014, are becoming more common. Sony Pictures’ computers were hacked in 2014, which resulted in numerous leaks of data and included a threat of even larger-scale disruption attached to the release of the movie “The Interview,” which was temporarily shelved. In 2015, international hackers stole as much as a billion dollars from over 100 banks in 30 countries. Nearly all the major internet companies have experienced large-scale hacking. Such incidents are not only becoming more common, but their reach and impact is expanding, often across international borders. To guard against these attacks as best as possible, companies must make serious and often expensive cybersecurity investments.

Some politically motivated attacks rise to the level of cyberwarfare. These can include attacks on populations, such as the sabotage of water, health communications, transportation, the electric power grid, military systems, financial systems and the stock market. Terrorist operations now routinely coordinate their efforts via the internet, digital media, and mobile phones, even using mobile phones to detonate bombs. A nation or group’s ability to launch a cyberattack can be seen as “a continuation of a high-tech arms race that has been going on since the invention of gunpowder,” says sociologist Rudi Volti. Cyber defense is now a critical component of government operations.

The openness of the internet, however, is critical to its functioning and central to its very identity. It was preserved through each iteration and innovation that allowed it to develop as a global system of communication and connectedness. Each link in the network stands on its own; the larger network does rely on any one portion for it to work. If state or commercial  forces were to wrest control of the internet, freedom of speech, the exchange of information, and digital literacy would sharply diminish, and existing social divides (socioeconomic, racial, ethnic, national) would deepen.

An open society can never be perfectly secure. Liberty and safety exist in a necessary, if at times frightening, tension. The internet and digital and social media exist at the intersection — powerfully, profoundly connecting us, in all the terrible and glorious ways that intricate social connectedness has always wrought.

There’s much more on terrorism, crime, the internet, and social connectedness in Chapter 5 of Superconnected.