Made ya' look!
NUDE is a marketing acronym:
Novelty
Utility
Dependability
Economy
There has been some very interesting research on this model, and one very interesting result stands out against all the rest, namely, if you rate your business in each of these 4 categories on a scale of 0 to 100, and your score is over 312, you will get enough referrals for your business that you won't have to ever buy advertising again. At least as long as you maintain a high score, anyway.
This appears to be a threshold effect. Anything under 312, and you get very few referrals. But a score of substantially more than 312 doesn't help any more than just barely 312.
Another interesting thing about this is that each of these 4 categories is perception, not reality.
There is no way to get a perfect 400, because the 4 categories have two opposing pairs. Novelty vs. Utility is a problem. For instance, when the fax machine was first introduced, it was certainly novel, but people's reaction was, "Why would anybody want to send documents over the phone?" Nowadays, the fax has recognized utility, but it's no longer novel.
Dependability and Economy have similar tradeoffs. Something might be extremely dependable, but too costly, or very inexpensive, but not sufficiently dependable.
Next time you embark on a marketing campaign, either online or off, try evaluating it using the NUDE model.