Online safety seems to be a buzzword at the moment with governments and the big website developers launching initiatives to protect children from online predators.
But a new report from Which? says that adults also need to be careful when using social networking sites as giving away too much information can leave them open to identity theft.
The research revealed that important personal information can be easily viewed on publicly accessible websites, leaving internet users open to the threat of ID theft and fraud.
People who used the default privacy setting on websites such as Facebook, MySpace and Bebo were found to be particularly vulnerable, as fraudsters are able to access every person in the same network.
And In The News says that, using Google, researchers were able to access the profiles of thousands of MySpace and Bebo users.
The reports suggests that fraudsters able to gather personal information using Google searches can then take this information and use it to discover vital security knowledge such as passwords and pin numbers.
"It was a real shock to see how much personal information about me could be found online, which could potentially be used by crooks to commit fraud", said Neil Fowler, editor of Which? magazine.
"We all need to take steps to protect our data - both online and offline - by being more aware of how our personal data could be used and taking care who we share it with."
The report also targeted companies such as Transport for London (TfL) and Virgin Mobile, who were criticised for failing to inform their customers about the use of their data.
The research, for example, showed that TfL doesn't inform users of the Oyster Card system that it records their journey data.
Virgin Mobile put its sharing of customer data down to a desire to "develop your service for the future".
However, In The News suggests that, by retaining this information, both of these companies may be in contravention of the Data Protection Act.
Mr Fowler added: "Which? is concerned that some private companies aren't complying with the Data Protection Act and we urge them to tighten up their processes so that consumers can be reassured that their data is in safe hands".
The report recommends that internet users regularly check their bank and credit card statements for unfamiliar transactions, using a shredder for documentation no longer needed and refuse to give personal or bank details to third parties.
Internet users should also try to provide only the minimum details on social networking sites, the publication warned.