Unlike similes that use the words “as” or “like” to make a comparison, metaphors state that something is something else.

Example:

A good book is like a good meal.- A simile suggesting that a book may be as ( mentally) nourishing and satisfying as a meal.

A wire is a road for electrons. - A metaphor suggesting that electrons actually do use a wire as a road to travel on.

Visual-driven ads have done very well with metaphor. Here’s one lovely example, part of a campaign for Sony Noise Cancelling Headphones done by Bagby and Company, Chicago:

By directly equating a noisy child with a loudspeaker, the ad demonstrates Sony’s empathy with modern travelers, and thus predisposes those travelers to trust Sony’s solution over the competition’s.

But metaphor can just as easily live in words. Here’s a great metaphorical headline, produced by Martin/Williams, Minneapolis for L.L. Bean’s dog beds:

Another example, from Carmichael Lynch, Minneapolis for Harley-Davidson:

Crispin & Porter produced this wonderfully minimalist campaign for a homeless mission in Miami:

And the Martin Agency in Richmond used metaphor to celebrate John F. Kennedy’s role in putting the first man on the moon: