LinkStation is the name of a series of NAS devices from the same company as the Kurobox. LinkStations are, as opposite to the Kurobox, ready-made consumer NAS and come with a build-in hard disk and pre-installed software. The Kurobox actually came into existance when Buffalo/Melco was sitting on to many LinkStation spare parts, and decided to flock them off to Linux hackers to get rid of the parts.
LinkStations are not intended to be hacked. Since, however, they are mostly build on the same hardware and software platform as the Kuroboxes, they have a lot in common. Not all LinkStation versions have equivalent Kurobox cousins, because Buffalo only sells selected hardware under the Kurobox name. For example, there is a MIPS processor LinkStation HD-HLAN, while all Kuroboxes are based on a PowerPC processor. Still, even the MIPS based LinkStation can in large parts be hacked similar to Kuroboxes.
Another hardware difference for quite some time was that LinkStations are and were always available with 110V (120V) and 220V (240V) built-in power supplies, while the Kuroboxes until recently only had built-in 110V power supplies. The current Kurobox HG-WR now comes with an external, universal power supply. The Kurobox is still not available with a built-in 220V power supply.
Buffalo/Melco has occasionally indicated that they are not too happy about people hacking their LinkStations, citing warranty and liability reasons. The LinkStation hacking community has never been "recognized" by Buffalo/Melco. This might be the reason why the LinkStation hacking community traditionally keeps a little bit separate from the Kurobox community and doesn't feel welcome.