It's a Hard Drive, you can read and write from and to it.
|What doesn't work:|
It's got "Smartware" built into the firmware that is useless in Linux and can't be removed. Every time you plug it in it mounts a read only virtual CD which while pretty much harmless is annoying.
|What was done to make it work:|
I added this to my fstab to keep Smartware from auto running.
/dev/sr1 none udf rw,noauto 0 0
I'm kind of disappointed with WD for this one. I'm glad I got it for cheap.