Every now and then you come across a product that is, what’s the word I’m looking for, compelling? intriguing? wWay cool? Today’s topic is a product that is all of those things. It is the $99.95 Eye-Fi Secure Digital (SD) memory card for your camera that has built-in wireless networking. Once configured, the card will log on to your Wi-Fi network and automatically upload images to one of a number of popular photo management tools or storage services such as Flickr and Picasa.

To say this is a cool idea is an understatement – it is a great idea! In this tiny package you have 2GB of flash storage and a wireless system that can log on to secured 802.11b, 802.11g and 802.11n wireless systems and intelligently transfer data.

A minor digression: The Eye-Fi comes in ridiculously tricky packaging – you pull the tab on one side and the quick start documentation appears as the actual Eye-Fi card pops out from the other side. Must have cost a lot, but why do it? Just when I think I understand marketing . . . . 

Anyway, the card comes with a USB SD card reader. When you plug the Eye-Fi card into the reader and the reader into your Windows (XP or Vista) or OS X (10.4+) machine, the device appears as a removable storage device that contains the installation software and full documentation.

The installation process installs the Eye-Fi Manager you use to configure the card. The architecture of the Eye-Fi system is quite sophisticated, with connections being established and dynamically managed between the card, the Internet-based Eye-Fi servers and the local Manager application. The Manager itself is a Web server that uses your local browser to create the user interface using the open source Dojo Toolkit.

The card communicates with both the locally installed Manager software and the Eye-Fi servers on the Internet, which route all image transfers to the selected photo service. The card can communicate with either endpoint depending on availability and can manage interrupted transmissions (important, as the card can only transfer images when the camera is powered on and within range of a Wi-Fi network).

The Manager communicates with the Internet servers to find out if images have been uploaded by the card from another network or when it wasn’t running. If the Manager finds it has images from the card that aren’t on the photo service it initiates synchronization.