Two-thirds of job applicants under 30 are not aware that employers conduct online searches of candidates, although they are the age group most likely to say their Web presence might need to be cleaned up, according to a new survey.

Job Hunting in the Digital Age, a poll of about 600 current employees conducted by Harris Interactive for Adecco USA, found that 66 percent of workers in Generation Y (ages 18 to 29) are oblivious to the online background checks employers do to research potential employees. In comparison, only 40 percent of baby boomers (ages 43 to 61) are unaware of such searches.

"The baby boomer in the workplace wants to be perceived as 'with it' and technologically savvy," said Bernadette Kenny, chief career officer at Adecco, a career-services consultancy. Therefore, more baby boomers make the effort to keep up with the latest hiring trends, as opposed to those in Generation Y just entering the workforce, according to Kenny.

On the other hand, the survey found that one-third of Generation Y employees admit there is something in their online persona -- whether a personal blog or profile on social networking sites  like MySpace or Facebook -- that should be cleaned up. Less than one-quarter of baby boomers say the same. However, 56 percent of all employees think online background checks are unfair.

So why should employers be concerned with workers' personal online lives in the first place? "I think they care because they know that their customers are doing the same kind of research," Kenny said. "You want the face to the customer to be the perfect face."

Job applicants should expect employers to do online searches of job candidates, Kenny said. Some things employers might look for are poorly written blogs or a discussion of experiences that are not professional. "I think a red flag would be anything that is indicative of an individual's lack of professionalism," Kenny said.

While baby boomers are most aware of online background checks, they are least likely to know what to do about it. Almost three-quarters said they would not know how to clean up their online persona, compared to about half of Generation Y.

Kenny suggested that people put themselves in a potential employer's shoes. "I think the applicant has to do their own Google search," she said.

Yet, being aware of what's out there is only a partial solution. "I think the biggest message for the current employee or the future job seeker is to be aware on a regular basis of the professional persona that you're projecting," Kenny said. "Your reputation is the single thing that you can control in your professional life."