It appears the major sticking point concerns the depth of the memory layer on which data is written: HD-DVD favors a datalayer 0.6mm beneath the surface of the disk, the same depth as on the current generation of DVDs.
Unlike Blu-ray, which has a much shallower (and therefore a more delicate) datalayer, an HD DVD has its digital information etched deeper beneath the surface just like a conventional DVD and can therefore be stamped out on much the same sort of equipment as a DVD.
The most established technology related to tracking social media comes from Autonomy's Intelligent Data Operating Layer (IDOL) platform, which has been scanning the Internet using techniques based on patterns and probability for more than a decade.