I have just read a story in the paper about police taking action against someone using Facebook. The story claims that this is the first time the police have used Facebook to serve a summons. It might be a first for the police, but they're a long way behind other enforcement bodies!
Think about it.
In 2010 there have been stories in the news about the employees of large banks setting up fake Facebook accounts to track down bad debtors. It might be harder for a bank to get the money you owe if you are overseas, but do you want to be afraid to come back for six years?
As an aside – Did you know that debts are not enforceable after 6 years?
Keep that in mind if you are being harrassed for something that is donkey's years old.
Then there have been a few cases around the world where 'anonymous' people have commented on forums or blogs online saying some really nasty things about other people, and been caught. You can get an order from the court ordering an internet service provider to disclose the identity of the person holding the account if that person is breaking the law. You'll have to collect the evidence and show that there is a real prospect that the account holder would be found to have broken the law in some way.
It is possible, and it has been done.
And it hasn't just been the banks. Some lawyers are seeking orders from the courts for permission to serve documents online. You can't very well post a comment to a friend and then say you didn't see a post attaching court documents. That story just won't wash.
You create profiles all over the place. Who can find you? Just about anyone! You might not make the first page of Google for a search on your name, but keep looking. I've found dance competition results that are almost 10 years old!
Once something about you is out in the ether, its hard to get back, if not impossible. If you are online, you can be found.
What is the future going to be like for our children when something like 21% of children have an online presence before they are even born, thanks to parents posting ultrasound photos online.