Practical holographic storage?

Coming from GE. 500GB per disc to start. [Link]

If you're keeping track, 500 gigs is about 20 times as much data as can fit on a standard Blu-ray disc. GE has had these holodiscs for a couple years now, but the breakthrough announced today was a system that can read and record data at the same rate as Blu-ray, making commercial use of the technology practical.
Holographic storage is absolutely nothing like CDs, DVDs, or Blu-ray, except for the part about a spinning plastic disc and a laser. Instead of bouncing said laser off of the disc to read out ones and zeros, a holographic disc stores data in three dimensional patterns (holograms) inside the material of the disc itself. To read the data, a holographic drive uses a laser to generate a sort of snapshot of the data stored inside the disc all at once, and multiple snapshots can be layered on top of one another to increase storage density.
Since GE has the entire volume of a disc to play with, 500 gigs is by no means the upper limit on holographic storage. They've barely kicked the current generation out the door, and already GE research teams are looking forward to blowing past a terrabyte per disc in the near future.