All HDMI cables are the same, but that now-ubiquitous connector has limitations. Ultralong runs can be problematic and expensive and HDMI cable can't conveniently be run through walls.
That's part of the message the people from HDBaseT sent when they introduced me to their transmission protocol this week. HDBaseT is designed to allow a single Cat 5e cable -- incredibly common and incredibly cheap today -- to carry video of up to 4K resolution, audio, data (100BaseT Ethernet), power (up to 100 watts), and even other signals like USB. Runs can be as long as 100 meters (328 feet), and passive repeaters can extend it even farther.
Update July 10: HDBaseT's presentation also said HDMI could only handle 4K video runs of "a few meters." CNET blogger Geoff Morrison, however, used a 40-foot HDMI cable to pass 4K resolution video, so that claim seems to stretch the definition of "a few."
HDBaseT has been around since 2010, and has become popular with professional AV installers. HDBaseT adapters that extend HDMI signals are available today, but they're relatively expensive ($150 and up for certified versions).
Now the HDBaseT Alliance members, including brands like Panasonic (with a whole PDF catalog of pro products), Epson, Hitachi, Pioneer, Onkyo, Belkin, and Monoprice, aim to make it more widespread by putting the connector into consumer AV devices.
These include a "single-wire" TV (no power cable!) launched in Europe by a company called AquaVision, a slew of projectors, and a high-end AV receiver by Pioneer, which will be announced next week at CE Week in New York.
HDMI is perfectly fine for most people's systems, and the next version of that spec might allow much longer 4K cable runs. But for relatively inexpensive, extremely long runs today, elaborate home networks, or any other situation requiring extra connectivity and versatility, HDBaseT is a compelling solution.