John Harrison, a group manager at Symantec Security and Response, says that people should be concerned, because they're sharing more than they think they are.

Because social networks, public records, and high-profile security breaches are so prevalent, a lot of potentially sensitive information is just floating around the Internet.

"Each piece of information adds to the puzzle," Harrison says. "We don't throw everything out there at once, but it eventually comes together. For example, you may not put your full birthday on Facebook, but it's not difficult for someone to find out what year you graduated from high school and put two and two together."

In other words, you may not think you're sharing too muchjust a snippet here and a snippet therebut to a hacker, you're building an easily harvested online profile.

Protect yourself the easy way