The Eye-Fi Explore product relies on Skyhook Wireless's system of analyzing the signal strength of nearby Wi-Fi networks to extrapolate latitude and longitude. Eye-Fi ties that into their system to stamp images with locations. This deal also ties into Wayport's domestic network of 10,000 hotspots, most of which are McDonald's outlets, allowing free uploading via those systems. The purchase price covers one year of hotspot service. You can upgrade an existing Eye-Fi to the new feature for a fee. All three products work with Mac OS X Tiger and Leopard, and Windows XP/Vista.

Because Skyhook needs a live Web connection to look up the Wi-Fi environment, Eye-Fi can store the Wi-Fi snapshot when the picture is taken, and manage inserting the appropriate photo metadata (EXIF format) at upload for Flickr and other services that support geotagging.

Geotagging is a very popular idea, something that I'm quite taken with because it pairs the act of taking a photograph with the location at which the picture is taken, making a digital photograph seem a little less untied to reality. But until now, it's been generally quite involved to match a picture with coordinates. A handful of specialized cameras embed GPS chips, and there's software to facilitate other methods, but the cost and battery drain of GPS chips have apparently so far kept it from being a widely deployed feature, while the wonkiness of alternatives doesn't appeal to mainstream users.

Sony once sold this wacky GPS companion (which I just found out isn't available in either released model) that would track your location over time, and use that information to geotag images via a special software program that let you pair its stream of data with your photographs.

Eye-Fi and Skyhook are doing something almost the same, since the camera isn't capturing the GPS data, and the Eye-Fi isn't applying the information live, much of the time. But it's eminently more usable than the Sony system, because the Eye-Fi handles the assembly seamlessly for you.

Now there's just one thing to worry about. Think about this: McDonald's are everywhere, and nearly all of the U.S. locations have Wi-Fi. The Eye-Fi uploads whenever it can, as long as the camera is turned on. You're geotagging images without any effort. Okay, got it? So...you call in sick to work, and run off to take some photos. Your boss, using RSS to subscribe to your Flickr feed, not only sees your pictures as you wander the town, unknowningly promiscuously uploading them via quick-serve restaurants' networks, but also knows precisely where you are.

This makes me suggest that you might set your Flickr upload preferences to keep images private and your geotagging preferences the same. You can then expose the images you want for public consumption. The Panoptican is...us!