To get a true holodeck experience, you need some pretty advanced technology. Holodecks on Star Trek were described as using different technologies, but usually as a combination of light projection for the 3D images and carefully manipulated force fields so you could touch them. Sometimes items were described as being replicated and transported onto the holodeck and later recycled back into the replicator system. To keep from running into walls, the floor would act like a treadmill.
The article mentions that last one, but it seems to be the only technology that exists so far. Projecting 3D images is one of those things that perpetually 10-20 years away. And if we develop force fields, replicators, and transporters, holodecks are pretty much an interesting offshoot compared to the major implications that would come with those.
