Who is making the splash?

Lu Chuan says he would never hire people to throw mud at the competition.

If you are a soldier of a water army, you are invisible. You will not tell your family or colleague you love or hate this movie. All you're required to do is to talk a movie up to the sky, or malign one to the bottom and do it online. For every post, you'll be paid 10 to 50 Chinese cents.

Those who talk up are called "white water army", and those who talk down "black water army". White or black, they tend to be proud of their collective power, but not proud enough to admit to what they conduct with online anonymity. This accounts for the difficulty of actually interviewing an individual foot solider, but they are said to be mostly students or young people with lots of spare time.

A water soldier who devotes all his or her time to the job, though, can bring in somewhere between 1,000 to 3,000 yuan a month.

Those who do the dirty job are entitled to only 40 percent of what film companies spend on it. The rest goes to online promotion firms that act as the middleman. According to a People's Daily blog post, most of these firms have fewer than 10 employees. They rely on a massive number of account holders through online communication tools. Once they get a job, they subcontract it to the thousands who make postings to drown out legitimate appraisals.

Some of these firms claim that, with as little as 100,000 yuan, they can make a movie into the talk of the town. But, on the other hand, movie promotion makes up a small part of their business, albeit with a high profile.

Discerning readers can find traces, if not conclusive evidence, of "water army" activities. For example, they tend to give the highest score to one movie and the lowest to another one screened around the same time, or use the most extreme language in their commentary, yet give no detail to back it up.

They also tend to be new account owners, with little or no previous activity with the accounts. Bai Jie, a publicity official for CN Movie, says that most accounts that attacked Lu Chuan's movie were opened a day after the movie's premiere. But she cautions that firms managing a water army sometimes buy or keep legitimate accounts to increase the level of credibility.

For more coverage by Raymond Zhou, click here