ZPODD is short for Zero-Power Optical Disk Drive and is one of the features of the Serial ATA 3.1 specification. What this ZPODD technology allows for is to zero-out the power consumption of an idle SATA ODD to further the power-savings benefits. If the SATA device is completely idle, there's no need to feed it anything.
Of course, this feature isn't entirely useful to all since many systems these days ship without any optical drive. But if you have a SATA optical (DVD / Blu-ray) drive installed, these Intel Linux patches could be of benefit.
Lin Ming of Intel has been working on the patches for a while and he just published the fourth revision to them on the mailing list. He also has ACPI D3Cold state power savings patches too, which he ended up splitting out from the SATA ZPODD work.
The SATA 3.1 specification was published last summer. Besides Zero-Power Optical Disk Drive support, other Serial ATA 3.1 features were Universal Storage Module, mSATA, Required Link Power Management, Queued Trim Command, and Hardware Control Features.