Cross-promotion can be a powerful tool. McDonald's promotion of a new Disney movie with Happy Meal toys can lead to more buzz for the film, creating bigger box office numbers, leading to even more Happy Meal sales. Sometimes, though, the rationale for such alliances is somewhat less clear. Ford (NYSE:F), for example, has teamed up in the past with Dell Computer (NASDAQ:DELL) to offer a free computer with the purchase of a Ford Focus.

At first blush, Ford's latest marketing initiative also seems a bit off the mark. The automaker announced today that it is linking up with energy giant BP (NYSE:BP) in an unusual way. Beginning in July, the gas caps on all 2006 Ford vehicles will bear the words "Ford recommends BP" and the BP logo. For BP, the benefit here seems likely to be extremely small. As noted in today's Chicago Tribune, Ford owners won't even see the gas caps until they open the metal door at the gas station.

Still, if anyone benefits from the alliance, it will be Ford. BP heavily promotes its efforts in developing more environmentally friendly energy technologies. TV spots regularly remind viewers that BP is one of the world's largest solar concerns, and the firm's website is plastered with information on the firm's innovation in the areas of cleaner fuels and eco-friendly energy. Even BP's green and yellow logo evokes a sense of harmony with nature.

Ford is keen on being associated with innovation in environmentally friendly technologies, a trend that appears to have become fashionable of late with such firms as General Electric (NYSE:GE) announcing its own green initiative. Although the BP deal will have a limited impact at best in improving the automaker's environmental image, Ford can use all the help it can get. Of course, gimmicks can go only so far, especially when other competitors continue to push the envelope in the environmental arms race -- Honda (NYSE:HMC) announced yesterday that it has leased the first fuel cell vehicle for private use.

Dell is a Motley Fool Stock Advisor recommendation.

Fool contributor Brian Gorman is a freelance writer in Chicago. He does not own shares of any companies mentioned in this article.