What makes ambiguous advertising so elusive to viewers and potentially helpful to advertisers is the "Come again?" aspect of deciphering what a particular message means. Sometimes, the advertiser is intentionally ambiguous -- to raise intrigue, invoke associations -- and other times, an advertisement is simply downright confusing, riddled with misspellings, unintended gaffes and just a jumble of bad grammar. Nonetheless, ambiguity can be effective if it captures layers of meanings in one memorable slogan.

Statements Out of Context and Grammatical Deviations

Advertisers are often accused of taking shortcuts that ignore the rules of grammar and angle for people's attention willy-nilly of appropriate usage. Examples of these are sentence fragments that invite the reader to fill in the blanks, such as Volkswagen's slogan "Somewhere between tuxedo and birthday suit," which does not state anything definitive about the product, but requires the beholder to piece together an association. Apple's slogan "Think different" avoids using "differently," even though the adverb might have been more grammatically correct, because its intended message is to make you think about "different."

"Purposeful Polysemy"

A study in the Netherlands found that "purposeful polysemy," or the strategic ambiguity of certain ads, had the effect of appealing positively to targeted minorities such as gays, without the negative backlash that might have occurred if the advertising had used more explicit methods of reaching out to that population. Gays responded to the ambiguity positively, and felt that the ads spoke to their particular needs; however, the ambiguity was successful only to a certain extent. Heterosexual viewers of the same ads had a more negative reaction to the ambiguous gay-targeted ads, without being aware of the intended target audience.

Double Meanings

"Writing Classes" point to the occasionally effective, occasionally humorous and sometimes disastrous results of using words ambiguously in advertising. When an ad loads up a slogan or catchphrase with multiple meanings, it serves double duty in cementing the product in a reader's mind. When Sleepy's mattress company proclaims "For the Rest of Your Life," you are assured of an extraordinary sleep experience and a lasting product. However, some double play is more effective than others. IBM's "We Make It Happen" could have been a clever pun on being an IT industry leader, but to achieve it, "IT" would have to be capitalized and pronounced as separate syllables, making it clunkier.

"Weasel Words"

Contributing to the confusion of ambiguous meaning are weasel words, which seem to provide useful insight but turn up empty. Examples include words such as "up to," "can help," "part of" and "virtually." Dishes can be "virtually spot-free" from a certain dishwashing liquid, but it's possible that they won't be. A bowl of a particular brand of oatmeal "can help reduce cholesterol," but there could be other factors involved in the decrease. Further, a diet pill can help you lose "up to 50 pounds," but you might not lose any weight, and the ad would not be incorrect.