I had good luck with these at my wedding. Instead of disposable cameras, I put cheap digital cameras. It didn't take long for guests to realise that the pictures were appearing on a large tv, in a sideshow. People got a lot more creative when they realised they would be seen quickly, not weeks later.

I managed to get them working without proprietary software, too. The onboard script logged into WiFi and uploaded the photos over ftp.

Given their size and the level of tech at the time, it was pretty impressive.

Things like this were huge back in the days of PDAs. They had SDIO ports specifically for expansion. I had one for Wifi and another for Bluetooth on my Garmin PDA, so I couldn't use Bluetooth and Wifi at the same time, and both kept you from having non-volatile storage. If your battery died, your system was wiped because all the storage was in memory.

I got a Dell at the very end of the PDA era (the iPhone was already out, but was still ATT exclusive) that was super fancy because it had a CF card slot AND an SDIO port, so I could store data AND use my SDIO digital camera.

Yup. It was used to transfer photos from a camera to a phone back in the day when cameras didn't have wireless transfer features.

I still have a 4gb Eye-Fi that use just as an SD card to shuttle files out to my laser cutter. I assume the wi-Fi would be horrendously slow and insecure if it worked at all. Was pretty cool when we still had a standalone P&S digital camera though.

I recently looked into them. They seem shit. Dodgey outdated apps to make them work and such.

Things like this would be so useful in the tinkering community, so many motherboards and such use micro SD cards or USB drives as a primary storage device. Before I gutted my 3d printer and put a computer inside it, I had to schlep the micro SD card back and forth from the printer to the computer room.. being able to send it wireless would've been great. Looked into it at the time but as other have said all the current solutions are dog shit.

Yep, had one for my Treo in 2006

I thought it was cool.

The old Toshiba ones could run a WebDAV server on them and you could log in with a PC and upload files. Was pretty sweet in a flash cart.

Still use mine in my cannon point and shoot. (Just as a storage device though) The software support has long ago suckified when "cloud" became all the rage, but it was awesome to sync camera <-> PC without messing with adapters or cables.

So what does it do, exactly? Can it act like a NIC or something?

CompactFlash, too. I 'member looking at them for a Dell PocketPC I found at a garage sale.

There are also horseless carriages.