Jeanette Torres says the first lesson she learned in grad school was social media 101.
"The very first thing they told us was to change your email, clean up your Facebook because we have checked, and your future employers will check also," said Torres.
A CareerBuilder survey this year found 70 percent of potential employers used social media to screen candidates and more than half did not hire someone because of something they saw.
"Maybe drug use, inappropriate comments, or illegal activity," said Consumer Reports Sr. Money Writer Donna Rosato.
Of course, there are limits on how they can use what they find. Federal law bars employers from considering a person's race, religion, disability or age when weighing candidates even if they glean that information on Facebook.
Other rules vary state by state. It's against the law in some states for interviewers to ask you for your passwords; others might resort to something called shoulder surfing.
That is when the employer will have you open up your social media account and literally stand over your shoulder checking out your page.
"Um....I'm not comfortable with that," said Torres.
Still, one way or another, potential employers will be looking so Torres polished her profile, starting with pictures.
"I put on my professional cap on and I looked through my profile pictures and I said...I don't know, I kind of took that when I was 16 and I'm really not the same person," said Torres.
As for photos other people post of you, you cannot delete them but you can untag yourself. You can also use your page to carefully craft the image you want employers to see.
"For example maybe you do a lot of volunteer work," said Rosato.
In other words, accentuate the positive and eliminate and untag the negative.