The knowledge exchange platform, which was launched in March, allows users to post questions on various areas. There are currently 12 categories and 203 sub-categories, including sports, business, politics, education and science.

Users can also choose to provide their answers for others' questions. The platform adopts a mechanism for voting and evaluation by users.

Chiu Chun-wai, one of the six students who scored 10As at Queen's College, wants to know why some human organs, such as the lungs, are more easily attacked by cancer, while heart cancer is comparatively rare.

'I think it's important to acquire vast knowledge,' said Chun-wai.

'It stimulates your critical thinking.'

Vivien Tsui Wai-man of Good Hope School is interested in knowing if humans could migrate to somewhere outside the solar system within the next 100 years, while St Paul's Co-educational College's David Lui Tak-wai wants people to share their own definition of achievement.

While most of the straight-A students ask questions related to science or economics, Yu Sze-yuen of Christian Alliance Cheng Wing Gee College would like to find out why former US president Bill Clinton did not impose any military attacks on the Middle East.

Yahoo Hong Kong representatives said that they do not impose any censorship on Knowledge+ content.

'It all relies on users checking on each other,' said Samuel Pun, head of search production at Yahoo Hong Kong.

'If they find any offensive questions or explicit content, they can press the 'report' button next to the question. Then we will have a look and delete any inappropriate content.'

Currently there are 350,000 questions posted. Celebrities, such as film director John Woo, have also been invited to post their questions. His was: 'Why are people attracted to superheroes in comics?'

Last month, the website invited users to respond to a question by renowned scientist Stephen Hawking - 'In a world that is in chaos politically, socially and environmentally, how can the human race sustain another 100 years?'