This article is from the rec.pets.dogs: Breeding Your Dog, posted to rec.pets.dogs newsgroup. Maintained by Cindy Tittle Moore with numerous contributions by others.
Well, yes, but that doesn't _mean_ a whole lot. A registered dog, be it AKC, UKC, CKC, etc., simply means that it's parents (and their parents) are also registered with the same registry. This confers no merit in of itself, it simply means that the dog's parentage is known.
Most registries do not make any assertions of quality in the dogs they register (except for some limited breed-only registrations, but these are uncommon). They do not restrict the breeding of their dogs and hence there is no guarantee that a registered dog is a good specimen of its breed.
The AKC has just started a "limited registration" program whereby puppies out of such dogs are ineligible for registration. It remains to be seen what the overall impact on AKC dog breeds will be. Other registries have used similar programs with good results.