DO YOU know what your son or daughter was up to last night?
Granted they may have been safely tucked up at home, but do you know who they were communicating with online, and what exactly they were posting?
That's the worrying question posed to parents by the news that a dad is now suing Facebook for allowing provocative pictures of his daughter to be posted on the social networking site.
The man alleges that his 12-year-old may be in danger from child sex offenders after she posted the pictures of herself. He wants her page closed and -- if this doesn't happen -- Facebook to stop operating in Northern Ireland, where they live.
The case will confirm what many parents already fear -- that their kids are sharing far too much personal information online, with no regard for where it will end up or -- more worrying -- who will view it.
It's accepted that children and teenagers will post information on Facebook and other social networking sites that they would never reveal face-to-face with their peers, let alone with adults.
This generation -- raised on social networking via personal computers and phones -- uses the internet in a different way to their parents.
When older generations were growing up, their own parents knew exactly who they were hanging around with and -- most of the time at least -- what they got up to.
But this monitoring has all but collapsed in the brave new digital world. The experts have a label for this -- younger users have less 'digital reticence'. In layman's terms this means they lack 'cop-on' -- something that won't surprise most parents of teenage sons or daughters, the 'digital natives' of the Facebook era.
The older generation may balk at posting personal pictures, phone or address details and other 'private' information online, but such practice appears to be the norm for their offspring, many of whom shun the sites' privacy settings.
For its part, Facebook has stated that it's strongly committed to removing inappropriate content and when a complaint is made about such material it is taken down from the site.
But many may see this as a case of slamming the stable door long after the horse has bolted.
Given the nature of the internet once an image -- or any form of information -- is posted publicly, it is virtually impossible to control where it goes, who else obtains it and where it is reposted.
Facebook has a minimum age limit, which is set at 13. But it relies on new account holders to honestly enter their date of birth when setting up an account. This means that any computer-savvy under-13 year old -- and that's almost any youngster -- can set up an account if they really want to. It's difficult to see how this could be policed. It's been suggested that information such as passport details could be used to verify age. This, however, raises a whole further raft of privacy and legal issues.
The fact is that the best way to safeguard children online lies -- as it always has in the offline world -- with parents themselves.
Engaging with teenagers openly on what they post online -- and why -- is likely to be far more effective than a lawsuit.