Although the iPhone and iPad may indeed pack a whole plethora of features, they still lack a plain ol' USB port. This means that they can't share files with a Mac or PC via a regular flash drive. The iStick, however, isn't regular. According to its creators, it's the world's first Lightning-to-USB flash drive.
It is, of course, already possible to move content between iDevices and computers. You can use a Lightning-to-USB cable, you can send files by email, or you can upload content from one device to the cloud, then download back from the cloud to the other device.
The iStick, however, is designed to make things easier. First of all, unlike a cable, files can be stored on it. This means, for example, that you could load a movie from your computer onto it, then watch that movie on your iPhone directly from the iStick – you wouldn't have to actually load the movie into the phone's limited memory space, in other words.
It's also much quicker than loading to and from the cloud, and doesn't require internet access. Additionally, users don't have to set up an account, or worry about the security of data stored online.
The iStick (not to be confused with the smartwatch-like thing of the same name) is made by Hyper, which also manufactures the streaming iUSBport. The company is now raising production funds on Kickstarter, with pledge levels starting at US$65 for an 8GB iStick and ranging up to $199 for a 128GB model. A free iOS app is also required to use the stick.
It should be noted that iPhones older than the 5/5c/5s don't have a Lightning port, so an unmodified iStick won't work with them. If you own one of those older phones, you might instead want to check out the i-FlashDrive HD, which plugs into the phone's 30-pin connector.
More information on the iStick is available in the pitch video below.