I have read a few comments by audio, video, TV, HD film reviewers/engineers that content piped through a HDMI connection doesn't look or sound any better than a standard composite cable. They have all then said that it is probably still too early in the standard's implementation to properly tell, but I just found out about a feature that comes along with HDMI.
The extra feature is called HDCP which stand for High-Bandwidth Digital Content Protection. This means that the signal travelling along the cable from your HD player to your TV is encrypted. Thus preventing a signal recorder from being placed between the player and the TV to capture the signal. This is most certainly another serious attempt by the industry to stop high quality pirated rips of films appearing on the internet. My initial reaction was that this is a little bit subversive, so I did some more reading to findout more about HDMI.
The idea of HDMI is that video and audio is digitally transmitted along one cable to prevent electrical interference. I had some Creative speakers that where digital and could switch between a Digital and Analogue signal on the fly. When no sound was being played, I could turn up the volume and there was always much less static on the digital setting. Using the speakers at a standard volume setting however I never could noticed the difference just like everybody who has commented about HDMI so far. So that begs the question, was HDCP the catalyst for HDMI or was it is just an extra feature someone thought of when the HDMI standard was being written, we will probably never know, but I am fairly certain that the uptake of HDMI would be a lot slower if more consumers where aware of HDCP because this stinks of corporate capitalism.