Web forums or message boards, where like-minded users come together to discuss and share their experiences - about anything from pets to favourite food joints to parenting - has also become the stomping ground of unscrupulous marketers, scammers and identity thieves.

Unethical food stall owners, for instance, have been known to create multiple fake identities to sing fake praises about particular stalls on popular online foodie hangouts like Makansutra.

For instance, one user created a new identity, saying that he was a food lover who wanted to share his discovery of a new vegetarian stall - and even registered a now-abandoned blog to do the same.

He was found out and heckled by forum veterans.

These bad hats have also been known to have set up Web forums to try and steal their users' identities.

Though there are no reports of such incidents happening in Singapore, these cases have popped up elsewhere, like a Web-forum hacking that led to the discovery of unethical behaviour by employees of an European online gaming company.

How? By banking on a user reusing the userID and password on other sites.

Once the thieves have your userID and password, they try to access other popular or related services - like a bank's website - to see if the same userID and password works there as well.

Unfortunately, no anti-virus program or firewall will be able to protect you from such tricks - since no virus or worm is involved in the attack, said security firm Symantec's chief technology officer Mark Bregman.

Instead, such 'subtle, sophisticated' attacks go after 'the person', and not his computer, said Mr Bregman.

But here is where a liberal dose of common sense can help. For instance, if a newly set-up food stall miraculously has fans sprouting out from the virtual woodwork, all creating a new account on the forum in order to praise it, make sure your alarm bells start ringing.

Top guild decimated

A forum hacker running an information site for the online game, Eve Online, was able to guess the password of one of the leaders of the game's most powerful guild.

With his details, the hacker was able to read his victim's private exchanges.

The hacker found out that a number of the leaders of the guild Band Of Brothers (BoB) were employees of the firm developing the game, Iceland-based CCP.

The hacker originally tried blackmail, but when the company refused to give in, he went public with this information.

BoB was derided for exploiting such a relationship, and CCP had to make repeated apologies. It also took action against the employees.

This saw virtual genocide by the game's player base against BoB, forcing players to quit.