Job seekers are being warned to be far more vigilant over what they reveal on social networking sites, as it could cost them their career.
A fifth of IT executives admitted they have rejected applicants because of what they have posted on social media.
The annual study has previously found that almost 40 per cent of respondents' companies look at potential employees' profiles on social media sites - but this is the first clear evidence that candidates are being rejected because of them.
"The 21st-century human is learning that every action leaves an indelible digital trail," the Daily Mail quoted  Mads Christensen, Network Director at Eurocom Worldwide, as saying.
"In the years ahead, many of us will be challenged by what we are making public in various social forums today.
"The fact that one in five applicants disqualify themselves from an interview because of content in the social media sphere is a warning to job seekers and a true indicator of the digital reality we now live in," Christensen said.
The survey also revealed that while nearly half of technology executives say that their firms will increase their expenditure on social media in the next 12 months, only 23 per cent say they can accurately measure the impact of the investment.
It said that 74 per cent of respondents consider online PR to be important for their company's search engine optimisation, with 37 per cent saying it is very important.
The Eurocom Worldwide technology confidence survey was conducted online by member agencies of Eurocom Worldwide during January and February 2012.
A total of 318 companies replied, with approximately 80 per cent from European countries and 11 per cent from the Americas.
The report also found that most popular social media platforms used by technology companies were LinkedIn (74 per cent), Twitter (67 per cent), Facebook (64 per cent) and YouTube (56 per cent).