A good ad is one simple idea, with humanity in it, that connects with consumers, that represents the value system of a company and then can connect it with the consumer. We always say a brand is set of shared values. So if you can simply demonstrate your value system as a brand, so that a consumer could say, "Ah, our values line up. I vote for you, brand!" that's a good ad.
Source: An Interview with Donny Deutsch: http://www.portfolio.com/views/columns/the-world-according-to/2007/10/19/An-interview-with-Donny-Deutsch
Contributed by: ~C4Chaos