New study shows that one in five employers use the social networking service to research the information about job candidates.

A survey made by the CareerBuilder.com, an online job site, showed that 22% of 3,169 hiring managers are screening social networking sites to research their future employees. An additional 9 percent said they don’t currently use such sites, but plan to start.

The research showed that 34% of the managers who search their candidates on the Internet found information that made them drop the candidate from any short list.

According to the study’s results, the main cause of dropping a candidate is that the hiring managers discovered that the candidates posted information about them drinking or using drugs. In addition, posting provocative or inappropriate photographs or information is another reason why a candidate could be rejected from a potential jobs.

Amongst other reasons the hiring managers rated also poor communication skills, use of  discriminatory remarks related to race, gender, religion and sharing confidential information from previous employers.

24 percent of the hiring managers said that the network social sites helped them to solidify their decisions about the candidates.

The employers were mostly interested in the candidate's backgrounds supporting their qualifications for the job.

CareerBuilder.com Vice President of Human Resources at CareerBuilder.com, Rosemary Haefner, noted that the hiring managers use 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 recommends the following tips to keep your online persona in a favorable light: clean up digital dirt, update your profile regularly, include specific accomplishments, inside and outside of work and monitor comments.