The following 15 activities, all of which are facilitated by Facebook and other social networking websites, are causing lots of heartache and headaches:

1. Posting illegal activities. In the little town where I grew up, 30 kids recently faced the wrath of their parents, school officials, law enforcement, and the Boston media, all because someone posted their party pictures, which depicted underage drinking, on Facebook. It’s never okay to show illegal behavior.

2. Account hijacking. Phishers imitate the Facebook email template, tricking victims into believing they have received an official Facebook message. Once you enter your login credentials, criminals can take over your account, pose as you, and ask your friend for money. Always log into your Facebook account manually, rather than going through a link in an email.

3. Facebook bullying. It is so much easier to write something awful about someone than it is to say it to them personally. Words hurt. Vicious words have led to kids committing suicide. Friend your kids and see what their online dialogue looks like.

4. Online reputation management (or lack thereof). I’ve seen teachers, professors, students, officials, police, and others from just about every walk of life get fired because of words or pictures they posted on Facebook. Remember, if what you post wouldn’t pass the potential employer test, don’t do it.

5. Social media identity theft. When someone snags your name, posts a photo as you, and begins to communicate while impersonating you, the effects can be devastating. Grab your name on as many sites as possible, including Facebook. Knowem.com can help speed up this process.

6. Financial identity theft. Bad guys use Facebook to crack your passwords. Most online accounts use “qualifying questions” to verify your identity. These questions tend to involve personal information, such as your kids’, other relatives’, or pets’ names or birthdays. When the bad guys find this information on your Facebook page, they can reset your passwords and steal your identity. So limit what you post, and lock down your privacy settings.

7. Burglaries. Criminals have been known to check Facebook statuses to determine if potential victims are home or not. Publicly declaring that you’re not home creates an opportune time for burglars to ransack your house. Never post this information on Facebook.

8. Geo-stalking. Location-based GPS technologies incorporated into social media are perfect tools for stalkers to hone in on their target. Please just turn these settings off.

9. Corporate spying. By posing as an employee, setting up a Facebook group, and inviting all the company’s employees to join, the bad guy gathers intelligence that enables him to commit espionage from within the organization.

10. Harassment. This goes beyond bullying. In one example, a woman was on a camping trip and unreachable by phone when her Facebook account was taken over. The “harasser” wrote all kinds of desperate status updates posing as the woman, leading concerned friends and law enforcement to her house, where they broke down her door.

11. Government spying. Who is that new friend? The AP reports, “U.S. law enforcement agents are following the rest of the Internet world into popular social-networking services, going undercover with false online profiles to communicate with suspects.” Just don’t be a “suspect.”

12. Sex offenders. Facebook is perfect for sex offenders, who pose as real nice people until they gain their victims’ trust. Always be on guard, and do background checks, at least.

13. Scams. It’s just a matter of setting up a fake Facebook page and marketing it to a few people, who then send it to their friends, who send it to their friends. An Ikea scam hooked 40,000 unsuspecting victims with the promise of a $1,000 gift card. Like mom said, if it sounds too good to be true, it’s probably not true.

14. Legal liabilities. In New York, a judge recently ruled that material posted on Facebook and other social networking websites can be used as evidence in court, regardless of whether the posts were hidden by privacy settings.

15. Zero privacy. If you think for one second that what you post on Facebook is for you and your friends’ eyes only, you simply don’t understand how the Internet works. Many sites are capable of pulling data from the bowels of Facebook, despite any privacy settings you may have in place. And that data can be stored forever, which means that it can come back to bite you long after you’ve forgotten you ever posted it.

Robert Siciliano, personal security expert contributor to Just Ask Gemalto, discusses hackers on social media on CNN. Disclosures