Using a weak password
Avoid simple names or words you can find in a dictionary, even with numbers tacked on the end. Instead, mix upper- and lower-case letters, numbers, and symbols. A password should have at least eight characters. One good technique is to insert numbers or symbols in the middle of a word, such as this variant on the word "houses": hO27usEs!
Leaving your full birth date in your profile
It's an ideal target for identity thieves, who could use it to obtain more information about you and potentially gain access to your bank or credit card account. If you've already entered a birth date, go to your profile page and click on the Info tab, then on Edit Information. Under the Basic Information section, choose to show only the month and day or no birthday at all.
Overlooking useful privacy controls
For almost everything in your Facebook profile, you can limit access to only your friends, friends of friends, or yourself. Restrict access to photos, birth date, religious views, and family information, among other things. You can give only certain people or groups access to items such as photos, or block particular people from seeing them. Consider leaving out contact info, such as phone number and address, since you probably don't want anyone to have access to that information anyway.
Posting your child's name in a caption
Don't use a child's name in photo tags or captions. If someone else does, delete it by clicking on Remove Tag. If your child isn't on Facebook and someone includes his or her name in a caption, ask that person to remove the name.
Mentioning that you'll be away from home
That's like putting a "no one's home" sign on your door. Wait until you get home to tell everyone how awesome your vacation was and be vague about the date of any trip.
Letting search engines find you
To help prevent strangers from accessing your page, go to the Search section of Facebook's privacy controls and select Only Friends for Facebook search results. Be sure the box for public search results isn't checked.
Permitting youngsters to use Facebook unsupervised
Facebook limits its members to ages 13 and over, but children younger than that do use it. If you have a young child or teenager on Facebook, the best way to provide oversight is to become one of their online friends. Use your e-mail address as the contact for their account so that you receive their notifications and monitor their activities. "What they think is nothing can actually be pretty serious," says Charles Pavelites, a supervisory special agent at the Internet Crime Complaint Center. For example, a child who posts the comment "Mom will be home soon, I need to do the dishes" every day at the same time is revealing too much about the parents' regular comings and goings.