Half of Facebook users add strangers as friends If there is one criticism that always crops up when Facebook is mentioned, it is the social network's convoluted privacy settings. The social network wants you to share your data widely with friends, family and beyond, both to encourage usage on the site and also to gather data which can be used to place adverts.
The plan has worked, with Facebook now set for a $100billion flotation.
But the more people share, the more they risk being hacked, or having potential employers or even burglars scout you out.
Which means it is a worry to read that 13million U.S. users have not even checked out their privacy settings - while, in the UK, half of people will happily accept a friend request from a stranger.
The U.S. magazine Consumer Reports said more than 13million Facebook users in the U.S. do not make any effort to shield their privacy, meaning they are likely to be unintentionally sharing their data with strangers.
Of the 13million, more than a quarter had their options set up to display their data to anyone, not just their friends and family.
Facebook has an estimated 188million users in the U.S., meaning about one in 15 users has never opened their privacy settings.
Meanwhile a report into the habits of UK users revealed that 90 per cent of us have received an invite from someone we do not know - and 51 per cent of us will 'friend' them.
Consumer Reports urged users to pay attention to their privacy settings.
Technology editor Jeff Fox said: 'Facebook really is changing the way the world socially communicates and has become a successful service in part by leveraging copious amounts of personal data that can be spread far wider than its users might realize.
'Our investigation revealed some fascinating, and some disquieting trends - but ones always worth knowing for consumers who wish to keep their personal data under better control.'
The report also identified that 4.8million users had posted a status update saying they would be spending the day, opening themselves up to the risk of burglary.
Another 4.7million have 'liked' a page which deals with health issues - and Consumer Reports points out that this information could be used against them by insurance companies.
Consumer Reports found that, in the U.S, nearly 40 million people identified their family members on their profile, 20 million displayed their date of birth, and eight million 'liked' a page relating to their religious beliefs.
Another four million would discuss their love life on their wall, while around 2.5 million people would discuss their drinking habits or their sexual orientation on their page.
The survey was carried out on 2,002 online households in America, of which 1,340 are active on Facebook, as part of Consumer Report's annual State of the Net report.
A separate report by Legal & General into the habits of UK Facebookers showed that nine out of 10 Brits using a social network have received a Friend Request from someone they do not know - and 51 per cent have accepted the requests.
Criminals are cottoning on, with reports of fake profiles being set up to find potential crime victims.
Mark Johnson of The Risk Management Group, said: 'From experiments TRMG have carried out, people are three times more likely to connect to someone they’ve never met if they have a mutual friend in common, due to something known as the Triadic Closure Principle.
'The level of attractiveness of online profiles, as well as ‘Liking’ similar groups or interests as targets, also increases the likelihood of people accepting or soliciting connections to strangers.
'Digital criminals are tapping into these insights in order to make their fake profiles as enticing as possible, creating a web of lies to hone in and ensnare potential targets.
'In some cases they even let the victims come to them, thus planting in the victim's mind the notion that the faked profile must be trustworthy 'because I chose to approach it'.
Michael Fraser, reformed burglar, star of the BBC's Beat the Burglar said: 'While people are becoming savvier about privacy settings on social networks, they can also develop a false sense of security with their online connections, wrongly believing they can trust all those so-called "friends".
'By turning a blind eye, people can unwittingly expose a wealth of personal information – a real goldmine for burglars. Digital criminals know how to spot easy targets - for example, someone with over 500 friends on Facebook is very unlikely to know all those people personally and will therefore be much more likely to accept a stranger’s friend request.
By befriending a number of the target user’s other friends beforehand, the victim is even more likely to accept the fake friend, inadvertently giving the burglar access to all their personal information.'