More and more people are signing up every day for social networking sites like Facebook and Twitter.

But as you're getting online, so are your employers, and if you're not careful with what you put on your profile, a local employment agency says that could be hurting your chances of getting a job.

"Prospective employers can really learn a lot about a potential employee's level of professionalism, conduct, or even cultural fit, just based on their personal blogs, webpages, or social networking sites," says Tara Marcelle, District Manager of Kelly Services.

And in some cases, negative information online has cost people job offers, or even worse, their current job.

That's why employment agencies are recommending you follow a few simple guidelines on your Facebook or Twitter page.

Marcelle says, "Candidates should really refrain from posting unprofessional photographs, refrain from using inappropriate language, or really staying clear of really controversial subjects."

But having a Facebook or Twitter account doesn't have to be a detriment to your job search, as it can actually be a benefit.

"Posting your resume, posting your education history, anything that you would typically use in a job interview, a cover letter, resume, anything like that, that's definitely great things to post on any social networking site," says Marcelle.

And even if your site is casting an unprofessional light, it's never too late to change it.

"Obviously, everything that's out there is out there forever, but it doesn't stay on their profile, their profile that they have out there, so that's why they should always update their profile on a regular basis," adds Marcelle.

And with the right care, your online profile can help get you a job instead of costing you one.