A new CareerBuilder.com survey found that 22% of all hiring managers have combed through social media profiles to help evaluate potential hires, up from just 11% two years ago. HR execs from media and creative agencies like MediaVest and AKQA weighed in on the practice, identifying LinkedIn as their site of choice for new hire research.

"We use LinkedIn a lot. It's like resume shopping," said Lionel Carreon, creative recruiter at AKQA. "Sometimes we'll ask candidates why they aren't on LinkedIn or Plaxo, because it's the easiest way to be found."

Carreon also said that the digital agency has hired employees they found through blog searches. "We look for some of the more serious blogs, particularly for positions like art directors and developers," he said. "Blogging about what they do and how they're being innovative makes candidates that much more attractive."

According to Tricia White, SVP and director of human resources at MediaVest, LinkedIn profiles can even substitute for resumes in some cases. "They both have a list of jobs and basic accountabilities," White said. "If I'm searching for a position like a media planner, for example, I can fill in the blanks with LinkedIn."

White said that she receives a few resumes every week through connections from her more than 3,500 LinkedIn contacts. "You'll get these people who say, 'I've always wanted to work for MediaVest and she's their top HR person, so I'll send my resume to her,'" White said. "It has become a fabulous tool for finding people who really want to be here."

Indeed, the CareerBuilder.com survey found that social media profiles could give some candidates a leg up over the competition. About a quarter of the respondents who had used social media in the hiring process said they found content "that helped solidify their decision" to bring in a specific candidate.

On the other hand, more than a third of employers that checked profiles said they had found content that disqualified a potential hire. The top three reasons for dismissal were that the person had posted info about themselves drinking or using drugs, posted inappropriate photographs, or showed that they had poor communication skills.

"We do end up finding things that make us say 'we're not going to bring this person in' about a third of the time," said Susan Misukanis, president of Misukanis & Odden, a Minnesota-based online marketing and PR firm. Misukanis said that the company went beyond destination sites like LinkedIn and Facebook in their screening process, combing through a candidate's Twitter or Plurk streams to get a holistic view of a candidate's personality.

"We look at their handles on Plurk or Twitter," Misukanis said. "They can be very telling, because they're quick sound bytes about how a person feels, what they like or don't like, and whether they're a generally negative or positive person.

She said that determining whether a candidate would "infect" the team--positively or otherwise--was a big part of why they dug a bit deeper online. "Anyone can come in and answer all the questions right during an interview," Misukanis said, "When they're on MySpace or Plurk or any of the networks, they're showing the world who they really are."

Rosemary Haefner, vice president of HR at CareerBuilder.com, agreed. "Hiring managers are using the Internet to get a more well-rounded view of job candidates in terms of their skills, accomplishments and overall fit within the company," Haefner said. "As a result, more job seekers are taking action to make their social networking profiles employer-friendly."

CareerBuilder.com surveyed nearly 3,200 hiring managers and HR professionals in late spring for the results.