Facebook has provoked anger from privacy campaigners by saying it will enable people to search for Facebook profiles via popular search engines - unless you opt out.

The social networking site seems to be moving towards being a directory of web users to boost traffic and subsequent advertising revenue. The changes mean that anybody who isn't a member can do a 'people search' from Facebook's front page, or can look for someone through a search engine - though they will have to become a member to interact with the subject of their search.

A Facebook spokesperson told The Times: "The Public Search Listing of a profile shows the profile picture thumbnail and links to interact with a user on Facebook. People will always have to log in or register to 'poke', message or add someone as a friend. A user can also restrict what information shows in their public listing by going to the search privacy page."

The site has been criticised by industry analysts for not maximising the earnings potential of the public information it holds. Facebook has almost doubled in size over the last 12 months and has over 7.6 million unique UK users, according to comScore.

Backlash

This latest news is another development in what has become an ongoing war between Mark Zuckerberg's social networking site and privacy campaigners. Last September the Mini Feed feature prompted controversy by showing users the recent activities of all their friends.

Earlier this year, Oxford University dons were criticised for punishing students who had put incriminating photos on Facebook. They used evidence from the feature that enables anybody within a network - in this case Oxford University - to see the complete profile of somebody else within that network.

Tech.co.uk recommends locking down your privacy settings so that only your friends can see your profile and personal information. We also recommend removing phone numbers and addresses from your profile. If someone really wants to get hold of you, they'll send you an email.