Hello 682194
Oddly enough 'HD Ready' was invented to try and demystify some of this jargon
Blu-ray Disc and HD DVD are two competing pre recorded high definition media formats.
HD is a catch all term used by many folk to describe video signals with a higher 'resolution' than was previously used for broadcast and pre recorded media.
There are approx 18 (I think) recognised high definition video signal formats - which gives broadcasters and pre recorded media and Display hardware manufacturers plenty of scope for producing non compatible hardware.
As high definition broadcasting and pre recorded media was beginning to emerge across Europe it was noted by lots of industry insiders that there were a lot of folk buying non compatible hardware - in particular the market was flooded with Flat Panel Displays (TV's) that were marked as being 'High Definition' but due to limitations on the Input side of these Displays (many of which were built with the US market in mind) they were never going to work with the high definition broadcasts being planned for roll out across Europe.
The governing body that looks after all things in relation to Broadcasting and pre recorded media across Europe (EICTA) decided to take a sub set of the global High Definition 'standard' and designated it as 'HD Ready' - this then meant all hardwired manufacturers in Europe could build to that spec and consumers buying Source devices and Displays could purchase kit marked as 'HD Ready' knowing that they had some level of guaranteed compatibility.
Armed with a SKY HD box, an HD DVD player and a Blu-ray Disc player consumers ought to still be looking to purchase an 'HD Ready' Display - it doesn't guarantee you will be able to make use of every feature of the new pre recorded formats but it does guarantee some level of compatibility and does guarantee compatibility with SKY HD.
As MAW mentions there are some features of the Blu-ray Disc and HD DVD technologies that go beyond the scope of the 'HD Ready' guidelines so anyone wanting to take advantage of those 'features' will have to ensure they have a Display that is 'HD Ready' and covers the additional features they are looking for.
See
http://www.eicta.org/press.asp?level2=24&level1=6&level0=1&year=2005&docid=398
Best regards
Joe