Symantec said a "digital tattoo" is created by all the personal information web users post online and can easily be found through search engines by a potential or current employer, friends and acquaintances, or anyone who has malicious intent. (See also "Five Ways to Defend Your Online Reputation.")
The security firm revealed that nearly two-thirds of all those surveyed had uploaded personal photographs, while 79 percent had at least part of their address online and nearly half had their mobile phone numbers online.
One in ten also admitted to have uploaded their bank details somewhere on the Web outside of online shopping sites and one in 20 have uploaded their passport number.
"In a rush to embrace the advantages of sharing information on the internet, many young people have created online databanks or 'tattoos' that much like a real life tattoo are extremely difficult to remove," said Caroline Cockerill, family safety advocate for Symantec.
"They either don't know or forget that much of the data is searchable by anyone, and in many cases legally retained by the sites themselves, or stored in caches, even when the data appears to have been removed."
Symantec said that nearly two thirds of all British Web users were concerned about the negative impact of their digital tattoo on their reputation, while 31 percent of under-25-year-olds admitted they were already wishing they could erase some of their personal information online.
However, older Web users are more savvy about their digital tattoo with less than a third of 36- to 45-year-olds sharing photos online and only 5 percent of those over 46 dared to post their photos on the Web.
Symantec advised Web users concerned about their digital tattoo to frequently check their privacy settings on social networking sites to prevent unwanted visitors from seeing anything they shouldn't.
The security firm also recommended Web users thinks before they post comments and images online, and should also avoid sharing personal information such as a date of birth or any information others could use to their advantage and your disadvantage.
"We see stories in the media on a regular basis about people losing jobs through flippant comments on social networking sites, right up to people in the public eye having inappropriate photographs online," Cockerill said.
"Social networking sites are great, but people should take a moment to think about what they're posting, and how it may have a long-lasting effect." (See also "Say Cheese: 12 Photos That Never Should Have Been Posted Online.")
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See also: Symantec reveals the web's 100 dirtiest sites