From body type and sex to hairstyles and clothes, you can add whatever personal touches you like. Some users have even added the physical attributes of humanoids or animals to their avatars. Creating your avatar is part of the fun.

With your real identity safely cloaked behind your online personality, the contrast between the virtual and real worlds can be striking. If you are a shy girl in real life, you can safely sport revealing clothes and wear flirty make-up. And a socially awkward boy can turn into an outgoing chatterbox.

Communication

There are two main types of text-based communication in Second Life: local chat and global instant messaging. The former involves conversations between avatars who are in the same place.

After a user types in his or her message and presses the 'chat' button, the words appear on screen and can be 'heard' by anyone within 20 metres. For those stuck in 'no-man's land', they can choose the 'shout' function which alerts others to their presence - these words are audible within 96 metres.

For global instant messaging, users engage in private conversations either between two avatars or members of a group. Physical distance does not pose any hurdles to this form of communication. Users can also plug in their stereo headsets and microphones and enjoy 'voice chat'.

Moving around

You can navigate 'The World' using the arrow keys on your keyboard and choose to walk, run or jump. To travel more rapidly, press the 'fly' button and hover above virtual establishments.

You can also travel in the various vehicles made by Second Life Residents for lease or purchase. The modes of transport on offer include cars, helicopters, submarines and hot-air balloons.

Another whimsical travel option is 'teleport'. Just as Japanese robotic cat Doraemon travels far from its cosy pad in suburban Tokyo at the turn of a doorknob, residents can travel from a concert in the US to a party at their friend's house in Hong Kong at a click of the mouse.

Virtual economy

With virtual banks, shops, currency exchanges and all kinds of commercial companies, Second Life has a thriving economy.

All transactions are done using the virtual currency Linden Dollars (L$) which, as of August, stands at about L$270 to one US dollar.

A buoyant real estate market where well-appointed houses and buildings change hands frequently between Residents enables users to reap virtual profits which can be exchanged for real money.

The commercial potential of The World has attracted multinational companies to set up virtual islands to promote their products, with some success.

IBM has recently bought 12 virtual islands whilst other big names such as Coca Cola, adidas, WWF and Reuters have also set up virtual outlets to reach out to the internet community.

Last year, Second Life recorded a gross domestic product of US$64 million.

Education

With colleges and universities setting up virtual classrooms, Second Life has emerged as the hippest platform for remote learning. Professors upload PowerPoint presentations and conduct lectures for student Residents and virtual libraries manned by real-life librarians, offer a wealth of knowledge. Hong Kong Polytechnic University's School of Hotel and Tourism Management launched an orientation programme there for freshmen in August.

Online lessons, covering topics from classroom etiquette and time management to avoiding plagiarism, are conducted in virtual classrooms where avatars of teachers and students converge at scheduled times.

Outside the fixed virtual class schedule, students can visit the information centres or chat with anyone they bump into in PolyUSotel (inset) to learn more about their school and campus life.

The flexibility offered by PolyUSotel has been welcomed by both teachers and students who are usually overwhelmed by a packed schedule in the first days of the new term. Criticism

Technical hiccups like long downloading time and difficult navigation have led to widespread criticism.

With unrestricted access and lax security, Second Life can also be a minefield of financial and other kinds of traps for gullible Residents.

With teens hooked on the virtual world, Second Life has also been criticised for alienating users from reality.