"Teach that sensitivity about how something that's out there might not be that easy to take back," said Sullivan. Knorr pointed out that with all the new geo-tagging applications that let people "check-in" to various physical locations, kids should also be careful to not post their friends' locations.
Learning how to share might be lesson no. 1 in kindergarten, but knowing when not to is lesson no. 1 online.
In the digital world, where information can be easily saved, stored and copied, Knorr said nothing is really private.
And kids – impulsive and inquisitive by nature – might be especially tempted to post inappropriate pictures, comments and videos online, she said.
In addition to sitting down with your child and making sure she understands what social networking privacy settings really mean, Knorr advised parents to tell their kids to "self reflect before you self reveal."
"You're in charge of your own privacy – anything you put up could be copied, forwarded and sent to those you never intended," she said.
The minimum age for opening a Facebook account is 13, but parents may be wise to start talking to their kids about online safety as early as 7 or 8.
When toddler-age kids start visiting preschool-appropriate websites, parents should actively monitor their online behavior, Knorr said. But as they get older and interested in social virtual worlds like Webkinz and Club Penguin, parents should start the conversation about online behavior.
"I think you start preparing well before they turn 13, in the same way I'm laying the groundwork for my kids before they start dating," Sullivan said. "You should have talked many times about the Internet and about the way identity can be manipulated online."
He also said that real-life examples can be used to teach online lessons. If a teen comes home upset that a secret shared with a friend was shared with others, he said, the experience could be used as a launchpad for a conversation on the implications of online sharing.
And remember that the conversation never stops.
"It's important to think about Internet safety, as a parent, as a constant dialogue in which you're giving advice to your teen or child that's appropriate to their age or environment," said Sullivan.
It's impossible to cover all the necessary ground in one conversation and, given how dynamic the technology is, the field is constantly changing.
But, he advised, keep lines of communication open with your children and stay on top of the technology in their lives.