Wang Yujing, 32, a policeman with the Jinhua public security bureau, updates his micro blog in his office in Jinhua, Zhejiang province.

JINHUA, Zhejiang - It doesn't take a celebrity to attract half a million followers on a micro blog.

Wang Yujing, a 32-year-old policeman in Jinhua, Zhejiang province, has not only gained popularity, but even helped save another policeman's life by circulating a post.

Wang, a micro-blogger with some 540,000 followers, posted a note last month looking for the donation of an O-type blood liver to save the life of a fellow officer.

In just a couple of weeks, the post had been forwarded 40,000 times and the officer was able to have a successful transplant.

"Wang Yujing's posts have helped so much, and I want to say thanks," said the officer.

Wang began micro-blogging to record cases he deals with every day and to give tips on public security.

"The number of followers counts, and followers can be powerful and quick to respond, but without adequate management of the information and smooth interaction, things can get complicated," he said.

"The power of micro-blogging surpassed what I had imagined, and I need to make good use of it," he said.

"People need information on public safety, and my posts cater to their needs, that's why I have so many followers today," he said.

He posts typical cases, warning about thefts, upcoming storms and giving tips for travel safety during holidays. Followers appreciate that his postings are "informative and helpful".

"Reminding people to take care of themselves and their belongings is an important part of my duty," he said.

He posted a note in mid-summer warning of the dangers of sleeping outdoors on a balcony. He depicted a case in which an elderly lady fell over the balcony last summer.

"Heat will hit Jinhua in a couple of days, and in past years some residents rest outdoors at nights. Please do not put your bed on the balcony or patio, risking your lives when enjoying cool nights," he wrote.

Similar cases happen every year, and hard lessons must be repeated before people remember, said Wang.

One of the latest safety tips was about antique collecting, as a man thought he found an antique at the construction site where he worked. However it turned out to be an anti-tank grenade that was buried several decades ago.

"It's likely that several other similar dangerous objects that were buried in the ground will be discovered in the future, so I think it can be a useful early warning," he said.

As a large group of residents in Jinhua are migrant workers, Wang spends a lot of time writing tips for them.

"Last week a young migrant worker chatted with a beautiful young lady via instant messenger online, and they spent a night after the chat. However, when the man woke up in the morning, he found that he was alone. The girl was gone, together with all his valuable belongings," he wrote in a warning against easy blind dates after online chats.

The girl's picture taken by the closed-circuit camera was also posted, together with a phone number of the officer in charge of the case.

"My micro blog can also be an information platform for gathering useful clues for police," said Wang.

Liu Liyun, a 23-year-old migrant worker in Hangzhou, Zhejiang province, said he logs onto Wang's micro blog twice a week to see what's new.

"His posts are quite helpful. I can always learn from them about how to protect my property and myself, such as how to identify frauds," said Liu.

Wang said he also studied how to attract a wider audience.

"Usually I write an eye-catching title, attach an impressive picture - without violating the privacy of people involved - and write a concise caption," he said.

Wang said he is also supported by many colleagues and senior officials.

Hua Naiqiang, political director of Zhejiang's public security department, told Wang to make his micro blog like "the business card of a Zhejiang police officers".