[Osiris]

My first thought when I heard about the Eye-Fi Wireless SD Memory Card was that no one would be going to need this SD card with build in WiFi but when I read a little bit further my opinion changed from No-one-needs-that to Wow-what-a-great-idea. The Eye-Fi SD cards come in sizes of 1 and 2 Gigabytes, the 2 Gigabyte version sells currently at Amazon for $99.99 which is way more than a SD card without WiFi would cost.
WiFi is of course what makes this SD card stand out of the crowd. There has been some confusion on how this actually works out and I would like to explain the principle. The SD card can communicate with a computer or the Internet directly and upload pictures taken with the digital camera to those locations. This means that no computer is needed after the initial setup if you want to upload the pictures to sites on the Internet.
Many popular photo sharing and printing websites can be configured using a software that is supplied with the SD card. A USB memory card reader is included with every card which means that you can plug the card into a computer and manage it from there. (Login and password for those websites for instance are stored on the card)
Supported are 40/104/128-bit WEP encryption, WPA-PSK, and WPA2-PSK encryptions and works with Windows XP, Windows Vista and Mac OS X. Only jpg images can be uploaded directly, images saved in other formats are currently not supported by the Eye-Fi SD card.

Eye-Fi Wireless SD Memory Card :

[atomic tofu]

this is old tech news...for me
but I haven't bought any because it tends to add a lot to the pricing

better to have the devices with the functionality built in...
Eye-Fi Collaborates With Nikon on First Camera Enhanced for Eye-Fi Card, Adds 'My Picturetown' To Eye-Fi Service

so I think it hasn't caught on too much only because of that...put it on the hardware and keep the memory cheap

[Saxon]

I saw chris perillio do a review on this, his view was good idea needs work though.