Engadget - The past decade has now seen at least three industry-wide technologies vie for the future of television -- HD, 3D and now 4K or UHD. The first of these -- HD -- represented a massive change for television that affected nearly every aspect of the TV experience from how it was captured to how it was consumed. A decade later, it is nearly impossible to purchase a TV that does not support high-definition. The second -- 3D -- was a mixed bag. While the technology became commonplace on high-end TVs, it has remained relevant for only a small fraction of programming. The question, then, is which of these paths, if either, 4K will follow.