Probably no one

 

Seriously. It’s a complicated and technically intensive way to spy on someone. Also, most of what you do on the computer is pretty mundane, so the chances that someone would want to watch you do it are slim. If you live near MIT or Caltech or somewhere else engineers are encouraged to indulge their worst impulses, someone may be watching you just for the hell of it.

If you’re a government agent, it’s more likely. Low cost, hard to prevent, and relatively low tech compared to many forms of electronic intelligence gathering, this kind of eavesdropping was made for poor but obnoxious countries. You can bet Iran and North Korea have homegrown geeks scattered all over the world, holed up in hotels near sensitive buildings, tweaking knobs on an oscillator and trying to pull documents from computer screens in the British Parliament or the Pentagon. Of course, we’ve got our own geeks doing the same thing to them. We’re just doing it from space.

If you work in a highly competitive industry or in defense, this kind of eavesdropping is ideal for industrial espionage. Most government buildings are shielded. Large corporations have shielded rooms, too, with computers that are never allowed out and data that cannot be transferred to another machine. But even so, if you’re designing the next long-range bomber or guided-missile system or if you work for an oil company trying to discover new sources of crude, someone may be watching your home computer on the off chance that you send an e-mail with just the right information.