Cause marketing is what happens when for-profit businesses join together with non-profit organizations for a marketing marriage made in heaven.

Think of the perfect unions that sprinkled fairy dust of goodness (and dollars) across causes and businesses: Unilever’s Dove Campaign for Real Beauty, which developed the Dove Self-Esteem Fund to help young women develop positive body images; Product (Red), which Bono and Bobby Shriver licensed to brands ranging from Gap to Apple in order to raise money for the Global Fund to Fight AIDS, Tuberculosis and Malaria; and one of the original cause marketing nuptials – American Express Statue of Liberty Restoration, when American Express raised $1.7 million to restore the statue and Ellis Island.  When these marriages are right, nonprofits benefit from greater exposure, reach and resources, while businesses benefit from a “halo effect,” earning more loyalty from the customers they have and more interest from the customers they want.

But like all marriages, these unions can go disastrously wrong…and when they do, the stench can spoil the sweet smell of both brands.  For example, how about when Susan G. Komen for the Cure and Kentucky Fried Chicken tried to pair cancer research with the Colonel of obesity.  Huh?  And for a particularly odorific example, how about Groupon’s Super Bowl ads that actually lampooned (?) the causes of Tibetan freedom, preserving the Brazilian rain forest and saving the whales (maybe I just didn’t get the joke.)

As consumers increasingly demand that businesses show (and step up) their cause bona fides, cause marketing has become the consumer-facing aspect of corporate social responsibility.  Corporate volunteer programs are the flip side of the cause marketing coin, where businesses engage their employees – as opposed to customers – in their corporate philanthropy efforts.

So when cause marketing comes your way, see if it makes you want to raise your glass and toast to the happy couple.  That’s when you know it’s working.