Baidu and companies across the country are tapping a frenzy of nationalist sentiment, launching patriotic promotional campaigns as thousands take to the streets to protest against the Japanese government's purchase last week of some disputed islands from a private owner, islands China claims as its own.

Be it to drive traffic to websites or garner customer loyalty, companies have rushed to wave the Chinese flag to try to cash in on the worst anti-Japan protests in decades surrounding the islands, called the Senkaku by Japan and Diaoyu by China.

Clicking on the image on the Baidu site takes users to a special site (baodiao.baidu.com/) exclaiming "The Diaoyu Islands are China's!" and encouraging them to plant a virtual red-and-yellow flag on the islands via a special Baidu map.

The tally as of mid-afternoon on Tuesday: 3 million and counting.

Baidu is far from alone.

"Fine food belongs to the world; the Diaoyu Islands belong to China!" online food retailer Etaoshi.com proclaimed in a banner on its website.

The site of online retailer Dangdang.com opens up to a full-page announcement that the company is handing out 1 million free hand-held national flags with the books and other goods bought on its site, and highlights posts by customers on social media sites expressing their satisfaction at having received them.

"I bought two books on Dangdang and got a free national flag -- wow, I'm thrilled!" user Gao Wena said in a posting on Twitter-like site Sina Weibo.

WEAPON AND SHIELD

Bricks-and-mortar retailers are not to be left out.

The Silk Market, a Beijing institution selling fake designer clothing and handbags, was adorned this week with a banner declaring that it "boycotts Japanese goods".

A photo shared by one user of Sina Weibo showed a supermarket display for a local brand of toothpaste done up in the shape of a cannon, with a Chinese flag atop it and a sign in front proclaiming that the Diaoyu islands belong to China.

For some businesses, the flag is being wielded more as a shield than a marketing weapon.

Some outlets of Japanese-style noodle chain Ajisen (China) Holdings Ltd (0538.HK) carried banners earlier this week saying it was a Hong Kong company and was of the same ethnicity as its customers.

"We are just as patriotic (as you)", one banner read.

That did little, however, to ease investors' worries over the possible business impact from the protests, sending Ajisen's shares down by around 8 percent so far this week.

Many Japanese restaurants and shops across China have also taken down or covered up their signs and hung up Chinese flags to avoid becoming the target of rioters.

As for Baidu, its Beijing-based spokesman, Kaiser Kuo, said its microsite was also aimed at keeping things under control.

"The purpose behind putting up the site was to encourage people to express their patriotism in a more rational way, to renounce violence," Kuo said.

"Planting a digital flag to express your feelings on this matter of the disputed islands is a much better alternative than throwing stones or eggs or smashing cars." (Additional reporting by Melanie Lee and Shanghai Newsroom; Editing by Nick Macfie)

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