Microdots are a new anti-theft system. Each dot is about the size of a grain of sand, and etched with a unique serial number. Car manufacturers can firehose 105 dots all over their car — inside, outside and on engine components — and hence make the car extremely resistant to chopshopping, since it's nearly impossible to remove all the dots and they will unambigiously identify all the parts for ever. The privacy implications are revolting, of course, but I love the idea of being able to make "Ex Libris Doctorow" microdots that I can spray over my entire library.
The dots are as small as grains of sand, and the information on them can only be viewed with a magnifying glass. They're sprayed all over a car's engine parts, air ducts and other automotive nooks and crannies. The dots are visible with black light because Allen wants thieves to know they are there.