A picture of yourself smiling with friends at a party might seem innocent. But the insurance company could use the photo as evidence you are not as disabled as you claim, Comitz says. Such a picture also could sway a jury to rule against you.

"Jurors tend to think of disability as a state of total helplessness," Comitz says. "But even the most disabled person has moments of joy in life, and if that's posted it can be misconstrued."

Insurers can't see pages you've made private, but someone could still find photos of you on a friend's public page. And your right to privacy could go out the window if you're involved in a lawsuit with an insurer. Courts have ruled in some cases that private social media postings are discoverable.

Future of social media and insurance

Right now, vendors are building tools to automate the process of searching social media. Such technology would allow insurers and other companies to more easily mine data from Facebook, Twitter and other sites.

What will insurers do with the information? That's the big question.

Beattie says one possibility would be to use the information to create a "social networking score." This could help insurers gauge risk, just as companies use credit scores to help determine the risk a policyholder represents.

"That's not being done today, and I haven't found any insurer that admits to doing it," he says. "I think that would create a public backlash in the industry, and rightly so, because it's a little invasive."

Social networking data also may help insurers learn more about their consumers, says Arun Prasad, a senior manager at Deloitte Consulting. For instance, insurers could pinpoint the common interests of high-net-worth people in their 40s who live in a certain geographical region.

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Such information could help companies better target their marketing and communication efforts. Insurers may also monitor what consumers are saying about their companies and use social networking to engage with them.

"It's cheaper and faster to ask a group of people if they're interested in participating in a Facebook discussion than getting 50 people to come into a conference room," Prasad says.

This article was reported by Barbara Marquand for Insurance.com.