Insurance firm Legal & General conducted a survey of British social media users and found that 91% had connected online with someone they had never met, and over half (51%) had accepted friend requests from strangers.
Nearly two thirds (63%) of those who connected with people they didn't know did so because of a mutual friend in common, while a third (34%) accepted strangers because they were members of the same group, and over one in ten (11%) felt it would be "rude" not to accept the request.
Burglars are creating networks of fake profiles to target potential victims, as such connections allow them to uncover a variety of personal information about users and their whereabouts, making their homes an easier target.
The survey found that 56% of social media users had discussed an event, evening or holiday plans 'wall to wall' on Facebook, potentially providing opportunities for them to be targeted by criminals.
Almost a third (29%) also only update their status or tweet when they want to brag to their friends about an activity, rising to 43% among 18- to 24-year-olds.
Michael Fraser, a reformed burglar and the star of the BBC's Beat the Burglar, said that digital-savvy criminals are increasingly using social networks as a "goldmine" of information on potential victims.
"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'," he said.
"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."
Legal & General said an emerging trend of "Face-bragging", involving someone exaggerating or lying about elements of their life online, is putting people more at risk.
A third (33%) of those surveyed felt that it is easy to spot a 'Face-bragger', and almost a third (28%) claimed they have seen others doing this. However, only 5% of social media users admitted to doing it themselves.
Mike Lawler, the director for Legal & General's general insurance business, said: "'Face-bragging' can, in many cases, be entirely innocent - we all want to show off about new purchases and holidays. However, a laissez-faire attitude when connecting to mutual friends we've not met, and 'Face-bragging' more personal details than we should, is placing people at risk.
"Sophisticated digital criminals are now creating networks of fake profiles to engineer sets of mutual friends, to target individuals and their homes.
"Social media users are assuming it is safe to connect to mutual friends - even if they've not met them - but they are inadvertently putting their possessions and homes at a greater risk of burglary."
Legal & General carried out experiments involving checks to see if people would accept social media friend requests from people they had never met. On average, 60% of users accepted a friend request from a fake profile
The research also revealed that nearly half of social media users have never Googled themselves to find what information is available on the open internet, but of those that had, 17% had found information that they didn't think was publicly available. More than half (57%) were also unaware they anyone searching on the internet can access and read their tweets.
Mark Johnson, of high tech crime control specialists The Risk Management Group (TRMG), 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'."
Legal & General wants a verification system to be introduced for all social media users so that others know for sure who they are connecting with, therefore reducing the effectiveness of fake profiles posted by criminals and pranksters.
A verification system is already in operation on Twitter for high profile accounts, although the system isn't perfect as an account was recently posted on the microblogging site purporting to be for Wendi Deng, wife of Rupert Murdoch, but was later proved fake despite receiving the verification tick.
"It's frightening to see the lengths that criminals will go to in order to target victims' homes and possessions," said Lawler.
"So it's vital that we all take sensible 'virtual housekeeping' precautions to check what information is publicly available and that when we use social media sites it is secure. By carrying out regular virtual housekeeping, consumers can reduce the risk they are at from digital criminals."
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