"The YubiKey has been around for several years and it is a USB device which has a keyboard HID profile. That means the device is detected as a keyboard and not a mass storage device, as most USB keys are. It is often used for 2-factor authentication, with the possibility for generating one-time passwords in synch with an existing service or a user-created one. The YubiKey NEO is a YubiKey that adds NFC capability to the standard YubiKey.
The Yubikey NEO has 2 storage slots on device which are accessible by a capacitive button. A short press emits whatever is stored in the first storage position and a long press emits whatever is stored in the second storage position. I used simple static text passwords in my testing of the YubiKey NEO since I wanted the YubiKey to be a basically be a physical key. I wanted it to be able to unlock my Symbian phone and have the password for an external memory card.
Since the YubiKey NEO has a standard-sized USB connector, I had to use it with the USB OTG cable to interface with the Symbian devices. The implementation of USB OTG is available at device boot up so I could use it to unlock my phone instead of using the on-device keypad. I had similar success when using a password on my microSD memory and I was able to transfer it to another device and just use the YubiKey NEO instead of using the on-device keypad.
Using the YubiKey NEO in this manner was a nice proof of concept as a physical key for a Symbian device but needing to use a USB OTG adapter limited its ease of use. Perhaps using the YubiKey Nano permanently inside a USB OTG adapter might be a stop-gap solution until they make YubiKeys with a microUSB connector."