WD Scorpio Blue began distributing 2.5-inch hard drives for notebook with 750 GB capacity. This is the highest data storage capacity in the industry today in its class. WD Scorpio Blue 750 GB notebook computer designed for general use.
The drives is in the 12.5-mm form factor, so they will fit in notebooks and small form factor desktops. The new 1TB capacity doubles the 500GB capacity that had become the large capacity standard for 2.5-inch hard drives. They also deliver a high performance 3Gb per second transfer rate.

Review :

The 12.5mm height drives are not very common any more. Almost all laptop drives sold nowdays are the slimmer 9mm height drives, and many laptops can only accept the smaller size. All of Apple's portables that could accept a SATA drive cannot use a 12.5mm drive.
I'm surprised WD jumped out with a 12.5mm drive.