One in five employers looks up social networking information on potential applicants, according to a recent survey.

Job-hunting site Careerbuilder.com polled 3,100 people and found that companies are increasingly relying on a candidate's social networking pages to determine whether or not to hire them.

Of those who responded, 20 per cent said that they had looked up an applicant's social networking profile. An additional nine per cent told researchers that they plan to start checking profiles soon.

A third of those who look up social networking information had found details which led them to no longer consider the applicant for that position.

The two most frequently listed reasons for eliminating the candidate were 'use of drugs or drinking' and the posting of photographs deemed 'inappropriate' or 'provocative'.

Other reasons include candidates showing poor communication skills, bad-mouthing previous employers, lying about qualifications and having an 'unprofessional' screen name.

Conversely, the survey found that 24 per cent of those who checked profiles had found information which helped them to hire the applicant.

Among the most popular reasons were qualified background information, good communication skills and finding that a candidate would be a good fit for the corporate culture. Positive references and a professional page presentation were also noted.

The site suggests that job seekers tend to their networking profiles regularly, editing comments and removing friend or group links which may portray a negative image.

Careerbuilder.com suggested that users who wish to keep would-be bosses away from their pages should set the profile to 'private' to avoid snooping.