That's because your insurance company could be monitoring your accounts, looking for information that could raise your premium or even deny your claim.
Kurt Nordland never dreamed photos he posted on his Facebook page would create huge problems.
The pictures show him drinking a beer and relaxing with his friends at the beach.
But his friends weren't the only ones checking out his Facebook status.
Investigators from the insurance company paying his worker's comp benefits were watching his Facebook account too.
And soon after the photos were posted, the insurance company canceled his payments, cut off his medical benefits and Nordland had to delay surgery to repair torn cartilage in his shoulder.
"I was extremely surprised they could just go on your Facebook and pull these pictures out," Nordland said.
What Nordland experienced is a trend happening all over the country: insurance companies snooping on social media sites.
Depending on your privacy settings, they can conceivably see tweets, photos and updates on what you're doing.
If insurance investigators think you're dabbling in risky business, you could end up paying higher premiums.
Nordland's attorney warns that social-media "mining" is now becoming standard practice in the insurance industry.
"If they find anything that's embarrassing or anything they can use to paint you in a bad light, that's when it shows up in the case," attorney Gary Massey said.
The Insurance Information Institute says some companies do monitor people's social media pages, mostly to find potential fraud.
"Insurance fraud costs the insurance industry and consumers about $30 million each year," said Jeanne Salvatore of the IFI.
Finding fraud is a specialty for private investigator Steve Davis. When he's hired by insurance companies to root out suspicious claims, his first stop is often Facebook or Twitter.
He says he's struck "gold" many times.
He found pictures of a guy who looked like he was pulling kids around on an ATV, while collecting disability insurance for an injury.
And he found a woman who was tagged in photos taking helicopter-flying lessons. Investigators say she claimed she'd was severely injured.
"If you're going to claim that you have a severe injury and you post pictures of you doing something crazy, then shame on you," Davis said. "You shouldn't have those pictures on there and shame on you for committing insurance fraud."
Insurance industry experts say honest people have nothing to fear.
Even so, it could take time and effort to clear your name.
Nordland says he was honest and medical records prove his on-the-job shoulder injury was legitimate.
Nordland's attorney had to fight the insurance company over pictures before a labor board, and won.
Nordland says he hopes people are more careful and think before they post.