By Marc Cieslak
Reporter, BBC Click
Millions of people have posted photos and personal thoughts on social networking sites. But do these sites provide rich pickings for identity fraudsters, or are they just a bit of fun?
The UK is Facebook's fastest growing market
Social networking sites have enjoyed an explosion in popularity in the few short years since they first appeared. The most popular, MySpace, claims over 100 million accounts.
Facebook, currently the place to be seen, claims 35 million people use its site to blog, catch up with old friends and share photos.
These sites are a magnet to the online generation, who are often sharing information of an extremely personal nature.
But the sharing of this personal information has created a fuss in the media, and there is a growing feeling amongst internet security experts that users posting so much information about themselves online is inviting trouble.
"Social networking sites, we believe, do have some dangers if people don't handle their information properly," said Neil Munroe of credit reference agency Equifax.
MySpace is the UK's most popular social networking site
"There is information there which it's been proven that fraudsters will use to actually steal your identity, not necessarily on the internet, but in other areas."
With this warning in mind it is astonishing to some just how much personal information is shared by unwary users.
"The sort of information that people need to avoid in public areas on social networks are things like their mobile phone number, their mother's maiden name, their full date of birth, that sort of thing," explained Chris McCafferty of MySpace.
According to Mr Munroe this is the basic kind of information that fraudsters will use.
"They will quite easily take that information and build up a profile to start taking credit out in your name or even take over your account. They could, for example, pretend to be you and take money out of your savings account."
It is easy to avoid playing in to the hands of the people stealing identities - simply do not put any information that might be useful to a fraudster on your profile page, or anywhere on the web.
In the last year online banking fraud in the UK has risen by 40%, according to banking trade body Apacs.
But it is not just identity theft that users should be worried about, the online age presents new challenges in the workplace too.
Many employers are checking job seekers out online to see what they do when out of the office.
Oxford University staff checked Facebook for disciplinary offences
"When people are applying for jobs they should be very cautious and make sure that everything online does represent them in the best possible way," warned recruitment agent Belinda Walmsley.
"The big no-nos are criminal activity or evidence of drug taking. No employer is going to look at a candidate where that is evident.
"Then you have the things that are seemingly innocuous, for example a simple posting about being too drunk to make it into work. Obviously if a prospective employer was to see that, they would really question whether you were the right candidate to join their firm."
The issue of privacy is a sticky one. Take the case of University of Oxford university officials who trawled students' Facebook pages, searching for evidence of extreme post exam parties where students have a habit of getting more than a little bit boisterous.
On the evidence of several Facebook photos the university engaged in disciplinary action against a number of students.
Experts counsel people to consider their social network page as resembling an ad in a local newspaper and few would take out one to show off intimate details of their life.
So why do so many post so personal information online for the world to see?
"It's important to remember that you are in control of how public or how private you want your MySpace page to be," said Mr McCafferty.
"So you can make your entire profile private if that is what you want to do, and then only friends that you accept on your list will be able to see your profile."
In a similar vein, Mr Munroe from Equifax recommends taking a steps to protect personal information.
"Make sure that you are using privacy guidelines that are on the site. A lot of people aren't aware that the sites do offer privacy guards which you can use to actually lock down the people who can see your information.
"And don't post things like when you are going on holiday," he added.
Mr McCafferty agreed: "People should remember that they are in control. They are putting information up on sites. So don't put information up that you don't want the whole world to know."
Whether people exercise control to avoid junk mail, stalkers or identity fraudsters, knowing what information about you is on the web is imperative.
If you would not give the information to a stranger, do not put it on the web.