The World: Insider's View - China.(using celebrities for marketing)

The ubiquitousness of some celebrities means advertisers have to work harder to make sure the star's power applies to their brand alone, Nick Barham writes.

You'd be pretty happy if Yao Ming represented your brand, wouldn't you? One of China's most recognised and loved celebrities, and one of the few with global visibility as a basktball player for the Houston Rockets.

So, if you were Gatorade's marketing team and Yao was waving your beverage on posters across China, you deserve a pat on the back, right?

Except Gatorade's not the only brand Yao's fronting. He has also appeared in ads for McDonald's, Reebok, Tag Heuer, Apple, China Unicom (mobile network), Sohu (web portal), Garmin (GPS services) and Upperdeck (trading cards) in the past year. Some are one-offs, others are longer-term, but the overall effect is that when you see Yao in an ad, you think Yao, not the brand he's accompanying. Instead of Yao supporting a brand, brands are just giving him additional media space, and boosting his celeb status.

It is not just Yao's ubiquity that lessens his effectiveness for these brands, it is also his passivity. Few of the brands have brought him to life or suggested what relationship he has with them, lazily relying on his fame to do their work for them.

It is tricky using celebrities. Even when they are not getting busted for drugs, or losing when they should be winning, or carelessly using your competitor's products in front of the paparazzi, it can be tough to get real value from them. Too ...