Social media let us express ourselves in ways we never could before. We can “like” people’s photos and ideas with a click. We can share details of our lives in words, photos and videos right from our mobile phones. We can connect with people from all over the globe who share our interests.

While that’s great, there’s also a flip side. Being too open on social media can be a bad thing. Chances are you’ve done it. You’ve liked or posted something you regretted or tweeted something that someone considered offensive. Social media is so very public. And your digital footprint will always be there.

Misusing social media can cost you your career. Justine Sacco found that out the hard way in December 2013. At the time, she was a public relations executive for a multinational firm. She boarded a plane to South Africa and before she shut down her phone she tweeted: “Going to Africa. Hope I don’t get AIDS. Just kidding. I’m white!”

There was great outrage regarding this tweet globally. And because it caused her Twitter stream to come under scrutiny, other questionable tweets were found. She was fired from her job. Her reputation was shredded with that tweet. And now she will forever be known as that PR person who tweeted a racist comment about Africa and AIDs.

According to a study by Jobvite, about 90 percent of employers now use Linked-In as part of the screening process. And 66 percent are checking out candidates’ Facebook accounts and 54 percent are scanning Twitter streams.

How do you protect your career?

How you conduct yourself online is up to you. Mark Story, author of “Starting Your Career as a Social Media Manager” and a social media consultant at the National Cancer Institute, shares some helpful advice for job hunters and employees about social media. He says that in order not to hurt your career you should make sure you have a professional, public-facing profile like LinkedIn. And make sure that with the other social media accounts you post to, such as Facebook or Twitter, you are familiar with the ever-changing privacy settings so you can protect who sees what you post or tweet.

Some tips:

• Google yourself to see what is out there. You should then set up Google Alerts for your name. You need to know what is being said about you online.

• Check your privacy setting on social media, especially Facebook. You can adjust your privacy settings on Facebook to show only a limited view. Facebook just announced a privacy checkup for all its users, to address concerns.

• Be careful what you tweet since you don’t know who is reading your tweets. Your boss and hiring managers are on social media just like you. It takes only a second to search Twitter using “I hate my job.”

• Make sure your information is consistent on all platforms. For example, your printed résumé should match your LinkedIn profile, especially if you are looking for a job.

• You have to be very aware of what you post on social media. Posting good and/or bad company business in additional to inappropriate information can get you into trouble or even fired. Be aware of your organization’s social media guidelines or policies.

• Remember this: If you wouldn’t want your grandmother or pastor to see your tweet or photo on social media, then don’t post it.

It may save your career.