They mention chips and tattoos under the Keep Your Companion Animal Safe section, but don't mention it in the Dog section. That is odd.
There is no national tattoo registry, so a pet can't really be traced through one. They're mainly good for identifying an animal as yours. But first you have to find it. Nearly every vet clinic in America now has a microchip scanner that can scan the two main ones used in the U.S. (AVID and Home Again), the Candian ones, plus some European chips.
One thing to keep in mind: if you have your pet chipped at a low-cost Chip-a-Thon in the Safeway parking lot or something, you MUST register the pet, which does cost extra (but with AVID, at least, you can register several pets for one fee). If you get your pet chipped at your regular vet clinic and forget to register, the chip can be traced to that clinic. So, if you notify them that Fluffy is chipped, you didn't register her, and she's lost, they can track you down.
If you've changed your registered address or phone number since you registered the chip number(s), be sure to notify the chip registry of the changes so they can find you if necessary. Keep a list of your microchip numbers in a safe place or your personal phonebook, along with the toll-free registry phone number. If your pet disappears, contact them immediately (24-hr service, usually), & they will flag the pet as Lost or Stolen. (Note: AVID is the only American chip registery that has never lost track of chip numbers due to computer problems, FWIW.)
BTW, microchips are inert until a scanner is passed over them. They do not give off radiation or anything like that. They are about the size of a grain of rice and are inserted over the shoulders, under the skin. Chips cannot be read from a satellite unless they are the kind that have a battery pack attached.
Every time you take your pet to the vet for a checkup or vaccinations, have them check the chip to make sure it's working and still in place (they have been know to shift occasionally).
FYI: All animal shelters in the U.S. are required to scan every animal twice: upon arrival, and again before being euthanized. Most shelters also have at least a 3-day minimum holding time for animals, but chipped animals may be held longer if they can do so, and may also be given emergency veterinary care. Many shelters assume that if an owner was responsible enough to chip, they are very interested in getting their pet back.
Sue