• by Gaetano Pollice , January 2, 2009

Forget the year of the rat - 2008 was, unequivocally, the year of Michael Phelps. The darling of last year's Summer Olympics graced year-end covers of Sports Illustrated and GQ, claiming the titles of both sportsman of the year (the first swimmer to receive the nod) and man of the year. Beyond the chest-baring glamour shots, having won a record-breaking eight gold medals is just the gift that keeps on giving, for both Phelps and all the brands who want his mug to adorn their ads.

Some of the Saturday Night Live host's favorite things - or, at least, things he convincingly pretends to like - include: Subway sandwiches, PowerBars, Speedos, AT&T wireless cards, learning foreign languages via Rosetta Stone, Visa credit cards, PureSport protein drinks and sugary Kellogg's cereals. In its cover story, GQ noted that Phelps stands to earn $100 million during the course of his career. Last month's autobiography, No Limits: The Will to Succeed, is Phelps' third (Phelps, mind you, is but a tender 23-year-old) and the book alone is said to have netted him a cool $1.6 million.

But is Phelps diluting the power of his brand and, by extension, his value, by engaging in too many endorsements? The danger lies not in too many endorsements, but choosing the wrong ones, says John Gerzema, chief insights officer at Young & Rubicam and author of The Brand Bubble. "Michael must seek out brands that match his values, otherwise he undermines his integrity and simply becomes a paid pitchman," Gerzema says. "Celebrity endorsement in our culture still works, but only if it feels true. Tiger Woods matches well with Accenture because they both stress high performance. Michael Jordan and Hanes? Maybe not so much."

Though most Olympians come packaged with a sell-by date when it comes to endorsements, Phelps doesn't seem to have that problem as yet - he's already announced intentions to compete in the 2012 Olympics, which will extend his shelf life even further. If the attention cools off sooner rather than later, he can always bum cash from his mom, Debbie, who inked a six-figure deal with women's clothier Chico's after the company spotted her wearing its clothes poolside in Beijing.

Maybe then he can afford a T-shirt for his next cover shoot.