"You don't have a tattoo on your chest saying 'Get It Here', do you?" -Blackadder
Enter the WayBack machine to 1987 and the original RT...
Electoos were quite common. Why settle for a boring tattoo when you can have one that lights up? A stacked crystal matrix is implanted in the dermal layers, powered by your own bio-electricity and with enough Thrones you can make your whole body light up! Think of the possibilities for the Adult Entertainment industry... One of the practical examples given was a "Thieve's Light", which was a "flashlight" built into the palm of one's hand. (10cm range, which was odd as O-RT was all in inches, but for N-RT we'll say 10' range?)
Skinplants (I'm straining, but I'm 80% sure that's what they were called) were the same stacked crystal matrix tattoo, but contained information. Personal information, medical history, credit ratings...you know, Mark of the Beast type stuff. Lighting up-optional. This is another example of Sci-Fi turning reality as we can do this now with RFID technology. According to O-RT it was common on many worlds and everyone on Holy Terra had one, which was automatically read every time you entered a building, bought something, etc. Also good for carrying coded messages.
Electrographs were again the stacked crystal matrix tattoos containing information, but applied directly to the Cerebral Cortex. A brain tattoo, if you will. Anyone with enough Thrones could get one, not just Tech-Priests (but I'll wager it would take a competant Tech-Priest to install one) and you could "buy" skills with them. Learn a new language. Hide a secret message. That sort of stuff. They were reprogrammable too, however frequent reprogramming caused erratic behavior and insanity...heh heh!
Sure, I'll let my players have one. Really want a skill that's not on your Advance Plan? Got lots of Thrones? Fine. First one is stable, each reprogramming will incur a Willpower test with a GM-Choice Modifier (that is, the more I don't want them to have it, the higher the difficulty will be). Fail that and you get reprogrammed AND d5 Insanity Points!
Ahh...the wonders of Dark Technology!