The information you really need to sound like a conversation-stopping geek is this: Blu Ray and HD DVD both utilize a BLUE laser which is physically smaller than the light of a RED laser. Hence, the information in the disk can be packaged in smaller pieces thereby allowing more data to fit on the same size disk! Get it?
The results are a lot of fun to see. We learn that HDTV was the inspiration for a successor to standard DVD’s which support enough data for standard format televisions. Once you try to digitally compress two hours of high-definition video, you discover that you need 22 Gigabytes of storage space. Even a dual-sided dual-layer DVD can only hold 18 Gigabytes.
Blu-Ray technology was developed in February 2002 to be DVD’s successor by a consortium made by companies that include Apple, Dell, Hitachi, HP, JVC, LG, Mitsubishi, Panasonic, Pioneer, Philips, Samsung, Sharp, Sony, TDK and Thomson. HD-DVD, on the other hand, was created by Toshiba and recently got support from Microsoft, HP and Intel.
When making the two disk types, the HD DVD makers folowed the measure of DVD where pits and lands, the 0’s and 1’s of the data, are deeper and farther apart than Blu Ray pits and lands. Also, disks, CD’s, DVD’s, Blu Ray and HD DVD’s keep information rolling in a spiral that begins in the center and runs out to the border of the disk. It’s just the opposite as LP records. So Track 1 is on the INSIDE of the disk, not the outside.
With HD DVD spacing pits and lands and the distance between spiral tracks farther, they have less potential to hold as much data. In terms of cost, HD DVD is the clear winner since they’re cheaper to produce.
With Blu Ray spacing pits and lands and the distance between spiral tracks closer, they are considerably more delicate. The layers between your Whopper/Cheddar popcorn coated fingers and the pits and lands are thinner since the 0’s and 1’s are physically closer to the surface.
A single-layer Blu-Ray disc can hold up to 25 GB, while a single-layer HD-DVD disc can hold up to “only” 15 GB. A dual-layer Blu-Ray disc can store up to 54 GB, while a dual-layer HD-DVD can store only up to 30 GB.

Did you know that PORN helped VHS over Betamax? It’s true, Betamax was staunchly against adult films being distributed in Betamax. VHS then, became the choice of the hundred-million dollar industry.
Blu-Ray’s maker, SONY, is staunchly against adult films being distributed in Blu Ray. Since SONY isn’t the only voice for Blu-Ray, there will be some explicit entertainment available. But already, the porn industry has discovered a growing market for movies on HD DVD!