Yesterday the U.S. Supreme Court threw out the conviction of a man sentenced to life imprisonment on the basis that key information used to prosecute him had been illegally obtained. 

A GPS tracking device, which reported its location via the cell phone network, had been placed on the defendant's car without a warrant. Four weeks of nearly continuous tracking provided the basis of an indictment and subsequent conviction for drug trafficking. In a victory for privacy advocates, the Supreme Court ruled that this tracking violated the American constitution's Fourth Amendment protections against warrantless searches and seizures of "persons, [and their] houses, papers, and effects." 

Because the decision did not fall along the usual conservative versus liberal lines, and because there are competing views among the justices on just how the Fourth amendment was violated, this case has provided a great deal of grist for the mills of court watchers (for an excellent dissection of the legal issues, see the SCOTUSblog's coverage.) 

But a broad swath of technology industries are also paying attention, as the court has taken the opportunity to clearly signal its interest in the Fourth Amendment implications of warrantless electronic surveillance through things such as e-mail records, GPS-enabled smart phones, or in-car assistance technologies. 

In this particular case, the majority decision of the court hinged on the finding that, by attaching a physical tracking device to the defendant's car in the absence of a valid warrant, law enforcement officials committed an act of trespass. But, even as they restricted their judgement to these narrow grounds, the judges warned that, "It may be that achieving the same [tracking] through electronic  means, without an accompanying trespass, is an unconstitutional invasion of privacy ..." 

Thus, while declining to say one way or another, it's likely that the court will accept for a review a future case speaking to these issues should one arise, which it it almost inevitably will, given today's fuzzy boundaries between public and private information. For example, just because I disclose my location to my cell phone carrier, is that information really  open for the police to peruse without a warrant,especially as disclosing that information is essential to using the service? And what about, say, nonessential but nonpublic information shared with a social network? 

What's clear is that the Supreme Court is aware of the often permeable membrane between a communications technology and a surveillance technology. 

Which particular such technology will ultimately fall under the Court's microscope is impossible to guess, but which ever one does, it's likely to produce a landmark ruling that will go a long way to defining the societal auspices under which these technologies operate, as they complete their transition from optional extras to essential products and services required by most people. 

The major failure of air-traffic control yesterday was yet another sign that our outdated radar-based system needs to be replaced with a sleek new satellite-based one, right? That's the logical progression of much of the coverage out there.

The reality is that, yes, the system needs to be replaced. But yesterday's failure was a high-tech one that could afflict a system based on satellites, too.

The problem wasn't directly related to radar, but with the National Airspace Data Interchange Network, a system for processing flight plans and information for all flights in the country. It failed in both of its locations: Salt Lake City and Atlanta. This meant that automated regional FAA systems couldn't process flight information. As a result, controllers had to enter information manually. This caused delays that rippled across the country. "A satellite-based system would have had the same problem," R. John Hansman, an MIT aerospace and air traffic control expert, wrote to me this afternoon.

The Federal Aviation Administration hopes to roll out a Global Positioning System-based control system, called Next Generation or NextGen, in stages. By 2020 most planes will carry a cockpit gadget that continuously broadcasts the planes' GPS-derived location, altitude, and speed to ground controllers. In later years, the system will extend so that this information is picked up by other planes, too, so that pilots can gain more control over their routing and spacing. As they beam their position information to one another they'll be able, to some extent, to self-navigate. However, there will always be an FAA air-traffic system keeping track. It's unlikely that pilots will ever be permitted to make all takeoff, routing, and landing decisions entirely by themselves in the event of failures of national air-traffic computers, as happened yesterday.

Yesterday at Yahoo's research headquarters in San Francisco, the company announced that it publicly opened Fire Eagle, its management system for location data. Previously, the service, which shuttles your location from your iPhone, say, to a microblogging service like Pownce, was only available to invited participants. Now that most of the kinks have been worked out, said Tom Coates, head of products at Yahoo Brickhouse, in San Francisco, Fire Eagle is ready for anyone to use.

With Fire Eagle, Coates and Yahoo are betting that location-aware technology is going to be big. The sort of future that Coates envisions is one in which your location can be broadcast to any website, added to your blog, and used to help you search for friends, news, and shopping deals nearby--all with your permission, of course. Fire Eagle, Coates said yesterday, can be the single place that a person needs to visit to set privacy requirements and make sure that the right type of location information (exact address, neighborhood, city, state, and country) is being displayed where you want it.

Here's how it works: if you go directly to the Fire Eagle site, you can manually set your location; if your computer, cell phone, or GPS navigation unit can find your position, you can have these gadgets send that data automatically to Fire Eagle. When Fire Eagle gets your location, it doesn't do anything with it until you select the Web services to which you want that information sent. For instance, if you have it sent to Pownce, Fire Eagle will update your location in your activity stream. If you allow Fire Eagle to send your location to a service called Radar, it can show you news stories that occur within 1,000 feet of your position. And there are a handful of services that can use your location information to help you see which friends (who also use the services) are nearby.

If these applications don't completely impress you, you aren't alone. Even at the Yahoo event, the people I talked to, mostly programmers and early adopters, weren't blown away by the demonstrations. The consensus is that the killer location application simply hasn't been invented yet. And only when that happens will location-aware technology truly take off.

In the meantime, Fire Eagle is playing an important role. Yahoo is offering a programming interface that lets software engineers easily integrate Fire Eagle into their existing service so that they don't need to build a location system on their own. Essentially, the services are bypassing months of work that it would take engineers to find the best way to read all the different forms of incoming location data (from GPS, Wi-Fi signals, cell-phone tower triangulation) and parse it themselves. Since Fire Eagle makes it easier for programmers to add location features to their software, this means that there will be more location-aware applications, and a better chance that truly useful ones will arrive soon.

Fire Eagle is good for users too. If you're interested in using any of these emerging location-aware services, you don't need to update each one independently: Fire Eagle will automatically send out the updates, based on your specifications.

Knowing that location-aware technology is a privacy minefield, Coates explained yesterday the three Fire Eagle features that his team has developed to give you a sense of control. First, you may choose to set the granularity of your location, ranging from your address to your country. Second, you can, at any time, "hide" yourself, meaning that your location data comes in to Fire Eagle but does not go out to any of your applications. Third, you may purge your data whenever you want. Fire Eagle does not keep a record of your locations; instead, it only stores your current position. The problem arises, however, with the applications that publish your location: they may keep your data as long as their terms of service allow. So even by purging your data from Fire Eagle, the trail you've left on the Web will still be visible.