The Video Electronics Standards Association (commonly known as VESA) is essentially the deciding factor on new hardware specifications and standards. Earlier today, they announced that they have approved Apple's new Mini DisplayPort standard, helped by the fact that it's a small connector and works well with small devices.
The announcement, found on VESA's website, states that, "Mini DisplayPort meets the need for a smaller form factor connector for devices such as thin portable computers and add-in cards with multiple display interfaces." Apple initially offered the standard in the form of a no-fee license, in which anybody could adopt, but decided to submit it to VESA for inclusion in the next DisplayPort standard update.
The standard was originally developed by Apple for use in its laptop range, such as the MacBook and MacBook Pro, and is progressing nicely; VESA stated that it's currently in the process of approving version 1.2 of the Mini DisplayPort, doubling the available bandwidth (meaning it'll be able to transfer 21.6 Gb/second). All going as planned, this should mean that in the future you might start seeing a lot more devices packing the Mini DisplayPort.